Objective To provide data on the incidence,shape,and sizes of the femoral attach.ments of meniseofemoral ligaments (MFLs),and to determine the function of MFIJs and the role in the femoral tunnel D0sitioning in the double-bundle reconstruction of PCL.Methods Anatomical study:Thirty cadaveric knees were used to investigate the incidence and tightening-slackening patterns during the knee nexion-extension of MFLs.Data were obtained to describe the size,shape,and the relationship between the position of the femoral attachment of MFLs and that of anterolateral bundle(ALB)and the posteromedial bundle(PMB) were detetrained.Clinical study:During arthroscopic reconstruction of PCL,the presence of MFIJs Was confirmed in 1 12 patients by observation and probing,the relationship between the femoral attachment of MFLs and that of ALB and PMB were determined.Results Anatomical study:The Humphry ligament and Wrisberg ligament were presented in l(3%)and 27(90%)case respectively.The femoral attachments were approximately ellipse both.The mean area was(18.14±3.05)mm2 and(25.63±7.92)mm2 respectively.Clinical study:The Humphry ligament and Wrisberg ligament were present in 2 cases(1.7%)and 67 cases(59.8%) respectively.The incidence of MFLs in knees with isolated PCL injury was highter than that in knees with multiple ligaments injuries.Conclusion The incident of MFLs is related to the trauma of the knee.and the Wrisberg ligament plays an important role in avoiding impingement between the ALB and the intereondylar roof during deep knee flexion.The Humphry ligament and the Wrisberg ligament are landmarks for the tunnel positioning of ALB and PMB in double-bundle PCL reconstruction respectively.

Objective To determine the biomechanical properties of anterior cruciate ligament allograft reconstructing posterior cruciate ligament in rabbits. Methods Based on the study of anatomy and biomechanics of normal rabbit cruciate ligaments, anterior cruciate ligament allografts were employed to reconstruct the posterior cruciate ligament in rabbits. The sterilized fresh-frozen allograft of bone-anterior cruciate ligament-bone were prepared and reserved for more than 14 days under -80 ℃. Twenty-four skeletally matured New Zealand white rabbits underwent a posterior cruciate ligament reconstruction on one knee randomly, the opposite knee was served as the paired control. Rabbits were sacrificed at 6, 12, 26 and 52 weeks respectively. Evaluations of the reconstructions and contralateral controls included the geometric, structural and material properties and rupture site. Results The mean length of the grafts at 52 weeks was 101% of the control (P=0.90), the cross-sectional area was 142%; the maximum load at 52 weeks was 83% of the control, the maximum elongation was 72%, the stiffness was 92%; the maximum stress at 52 weeks was 58% of the control, the maximum strain was 72%, and the modulds was 65%; the rupture site was all at the body part of the graft. The geometric, structural and material properties of the graft were gradually similar to those of the normal posterior cruciate ligament with the elapse of the time. Conclusion The biomechanical properpies of graft with similar material properties to normal posterior cruciate ligament following posterior cruciate ligament reconstruction in rabbits was favourable. The similar material properties of graft to normal posterior cruciate ligament play the very important roles in the posterior cruciate ligament reconstruction.

Objective To establish the animal model(rabbit) of shoulder instability for providing the experimental basis of related studies.Methods shoulder joints of 6 skeletally matured New Zealand white rabbits were measured with the anatomical characteristics and joint motion range in order to determine the operative approach,the similarities of skeletal structure,surrounding muscles,joint capsule and ligaments between rabbit and human were compared.Eighteen rabbits,weighing between 2.5 and 3kg were randomized into 2 groups(experimental group 12 and control 6).In experimental group,instability model was established by means of the operation procedure as follows:the glenohumeral joint of right shoulder was exposed by cutting the subscapularis tendon,then the anteroinferior labrum and surrounding capsular ligament were excised.For control group,sham operation was performed by only curing the skin and superficial tissue,the subscapularis tendon and glenoid structures was kept intact.The specimens of 6 rabbits were harvested 6 weeks after operation.The remaining rabbits of both experimental and control groups were killed 12 weeks post the operation for specimens processing.The motion range and instability were measured in all specimens.Results The gross anatomy of shoulder ioint in rabbit is similar to human.In experimental group,the stability is showed less than control,grade 2 anterior instability was found.The motion range was restricted in all directions,such as external and internal rotation,extension and abduction compared to control group.Conclusion Rabbit is suitable to establish animal model for shoulder instability and related iniuries,the animal model which was designed by this study could provide valuable information for the research of anterior shoulder instability.

Objective To measure and determine the position of the tibial attachment of the anterior cruciate ligament (ACL)in relation to its anterior ridge on the magnetic resonance imaging (MRI)of normal knee joints,and to explore the clinical role of the anterior ridge in guiding tunnel positioning during ACL reconstruction as well as in facilitating postoperative radiographic evaluation.Methods The knee MRI of one hundred young adult patients with an intact ACL and normal knee joint (mean age:25.1 years,range:18-40 years)was retrospectively reviewed.All MR images were obtained at full extension of the knee on the same MRI machine.Using digital image software on MRI,the measurements in the sagittal view were taken,including the depth of the tibia,the distance from the anterior edge of the tibial plateau to the most anterior and posterior portions of the ACL insertion on the tibia and the anterior ridge according to Staubli and Rauschning's method.Results The center of the tibial insertion of the ACL is located between 28.43％ and 50.94％ of the total anterior-posterior depth of the tibia,which was less than 43.3％ in 58 patients.The average distance from the anterior edge of the tibial plateau to the anterior ridge was 13.61 ± 2.17 mm (ranging from 8.03 to 18.65 mm),26.80％ ±3.89％ (ranging from 17.74％ to 33.94％)across the tibial plateau.There were significant positive correlations between the distance from the anterior edge of the tibial plateau to the most anterior portion of the ACL insertion and that to the anterior ridge.The distance from the most anterior portion of the ACL insertion to the anterior ridge was averaged 0.56 ± 0.68 mm (ranging from-0.28 to 2.71 mm).During the ACL reconstruction,with the anterior edge of the tibial tunnel determined at posterior 0.5 mm to the anterior ridge,the graft size as 8 mm,and the tibial guider angle set as 55 degree,96of the patients (96％)would have the center of the tibial tunnel located before the center of their native ACL attachment.Conclusions On sagittal MR images,the location of the anterior ridge and the most anterior portion of the ACL insertion correlated well,with the average distance between them of 0.56 mm.The study indicates that during ACL reconstruction,tibial tunnel drilling with the anterior edge of the ACL graft positioned at the anterior ridge can achieve a more anterior position than the traditional methods to orientate according to the center of the bone tunnel.

Abstract: Objective To investigate the molecular characteristics of the H9N2 avian influenza virus (AIV) causing human infection in Yunnan Province in 2019, and to provide the scientific basis for the prevention and control of avian influenza in Yunnan Province. Methods Influenza virus typing was performed by real-time RT-PCR in two influenza-like illness samples, and the Illumina Miseq high-throughput sequencer was used to determine the viral genome sequence. HA and NA gene sequence alignment and phylogenetic tree construction were performed using Mega7.0 software. Results Real-time RT-PCR results showed that two influenza-like illness samples were positive for H9N2 subtype. The full length of HA and NA were obtained by genomic sequencing. Sequence system evolution analysis showed that the HA and NA of the two AIVs in Yunnan Province were in the same evolutionary clade as A/Chicken/Zhejiang/HJ/2007 and belonged to the G57 type. The HA nucleotide and amino acid homology of the two AIVs were 93.92% and 95.00%, respectively, and the NA nucleotide and amino acid homology was 93.31% and 82.03%, respectively. The nucleotide (amino acid) homology of HA was 92.29%-96.94% (93.77%-98.43%) and 92.84%-94.92% (94.18%-96.23%), respectively, and NA nucleotide homology (amino acid) were 91.81%-97.60% (77.82%-94.83%), 94.38%-97.22% (85.47%-94.55%), respectively, compared with that of human infected H9N2 epidemic strains obtained in China from 2015 to 2020. Both AIVs HA protein cleavage site sequences were PSRSSR↓GLF, which was in line with the characteristics of low pathogenic influenza. The analysis of HA protein receptor binding site showed that amino acids at positions 109, 161, 163, 191, 202, 203 and 234 were consistent with the reference strains, while amino acids at position 198 were mutated to T. N166D and 168N mutations were also found in HA protein, and both AIVs had 7 potential glycosylation sites. Analysis of the erythrocyte binding site of NA gene found that there were amino acid mutations at positions 369, 402, 403, and 432, and amino acid deletion at positions 63-65 was found in the NA genes. There were 4 and 5 potential glycosylation sites in the two AIVs, respectively, and no drug resistance site mutations were found. Conclusions　The receptor binding sites, erythrocyte binding sites and glycosylation sites of HA and NA genes of H9N2 AIV in Yunnan Province have different degrees of variation, and monitoring and prevention and control should be strengthened.

Objective To investigate the expressions of cytokeratin/keratin 4 in the buccal tissue of oral submucous fibrosis at the early,middle and advanced stages,explore which role keratin4 (K4) plays in the process and development of oral submucous fibrosis (OSF),and provide evidence for K4 being a promising biomarker to evaluate the development and prognosis of OSF.Methods Ten cases of normal tissues,and 10 cases of OSF tissues with typical early,middle and advanced stages,were selected,respectively.Detect the expression of K4 in the tissue mentioned above through immunohistochemistry and Westem blot.The data was analyzed by statistical means.Results The results of immunohistochemistry showed that K4 was mainly located in cytoplasm,and positive cells with brownish yellow granules were seen in whole epithelial layer of the normal mucosa.The expression of K4 was lower at all stages of OSF than that at the normal tissue with statistical significance (P ＜0.05).With the aggravation of OSF,the expression of K4 was decreased,difference between early and advanced stage was found to be statistically significant.The results of Western blot also showed that the expression of K4 was lower than that of early,middle and advanced stages of OSF (P ＜ 0.05).With the aggravation of OSF,the expression of K4 was decreased,but the differences between them had no significance (P ＞ 0.05).Conclusions The expression of K4 in OSF tissue of early,middle and advanced stages were decreased compared to normal tissue,respectively.It suggests that K4 might play and important role in the initiation and development of OSF.

With the development of modern imaging technologies,three-dimensional (3D) reconstruction techniques based on the computed tomography (CT) or magnetic resonance imaging (MRI) data has been gradually applied in clinical diagnosis and treatment of hepatobiliary diseases.In order to study the characteristics of the 3 D model of portal branches and collateral circulation in various types of portal hypertension,the data of 64-slice spiral CT scan of5 patients with portal hypertension were collected and imported to the abdominal medical image three-dimensional visualization system (MI-3DVS) for sequence segmenting and 3D reconstruction,and then the results of 3D models were compared with operation findings.The 3D models were vividly,visually and clearly displayed the portal system and the collateral circulation,which is helpful in the diagnosis and treatment of the portal hypertension.

Objective To explore the effect of Ligustrazine on neurogenesis in cortex after focal cerebral ischemia in rats. Methods Focal cerebral ischemia was induced by left middle cerebral arteryocclusion with asuture. Two hours later, injection of Ligustrazine (80 mg/kg, 1 time/d) was performed peritoneally. Four hours after the ischemia,5-bromodeoxyuridine (BrdU) (50 mg/kg, 1 time/d) was injected peritoneally. At 7 d, 14 d and 21 d after ischemia,BrdU positive cells in the cortex were observed by immunohistochemical staining. Results In ischemic model group, at 7 day, sparsely-distributed BrdU positive cells were observed in the Ⅱ - Ⅵ layers of the ipsilateral cortex, with a band-like distribution in ischemic penumbra. With the prolongation of ischemia, the number of BrdU positive cells increased.In Ligustrazine group, BrdU positive cells were also observed in the Ⅱ - Ⅵ layers of the cortex, with an intense distribution in ischemic penumbra. The numbers of BrdU positive cells at 7 d, 14 d and 21 d were more than those in ischemic model group respectively. Conclusion Ligustrazine increases the proliferated cells in cortex after focal cerebral ischemia in rats. The results suggest that it may be useful for promoting self-repair after ischemia.

Objective To explore the influence of elevating the oxygen pressure on articular chondrocytes in vitro.Method A hydrogen peroxide induced human articular chondrocyte damage model was established.Then the articular chondrocyte viability was detected using the CCK-8 kit.Collagen Ⅱ(COL Ⅱ),The expression levels of aggrecan (ACAN),matrix metalloproteinase 13 (MMP13) and adisintegrin and metalloproteinase with thrombospondin motifs 5 (ADAMTS5) were detected using the realtime PCR and Western blotting.Result The viability of articular chondrocytes improved at 12 h but decreased at 24 h after the stimulation of hydrogen peroxide.Twenty-four hours later,the average expression level of COL Ⅱ and ACAN decreased(P＜0.05),while that of MMP13 and ADAMTS5 elevated(P＞0.05).Conclusion Hydrogen peroxide induced elevation of the extracellular oxygen pressure can influence the synthesis and degradation of the articular chondrocyte extracellular matrix.

Objective:To observe the expression of wnt1 in patients with oral submucous fibrosis(OSF) before and after treatment.Methods:40 patients with OSF were treated with triamcinolone acetonide combined with salvia miltiorrhiza,Before and after 4 weeks treatment,pain score of VAS and mouth opening(MO) were examined.wnt1 protein in saliva and gingival crevicular fluid(GCF) was examined by ELISA,wnt1 mRNA expression in buccal mucosa tissue was examined by real-time fluorescent quantitative PCR.20 healthy subjects were served as the controls.Results:The expression of wnt1 in OSF group[buccal tissue RT-PCR (36.89 ± 10.40) × 10-5,saliva ELISA (61.61 ± 4.45) ng/L,GCF ELISA (56.20 ± 3.65) ng/L] were significantly higher than that of control group [buccal tissue RT-PCR (4.63 ± 1.53) × 10-5,saliva ELISA (40.26 ± 3.00) ng/L,GCF ELISA (53.45 ± 1.74) ng/L)] (P ＜ 0.01).In OSF group,after treatment VAS was decreased(P ＜0.01),MO increased(P ＜0.01)),Buccal mucosa wnt1 mRNA level was positively correlated with wnt1 protein in saliva and GCF,negativity with MO (P ＜ 0.05),saliva wnt1 was positively correlated with VAS and GCF wnt1,negitively with MO(P ＜ 0.05).Conclusion:Wnt1 might take part in the occurrence and development of OSF.The detection of wnt1 in saliva and GCF might be a noninvasive method for the evaluation of OSF treatment.