The miR-17-92 cluster,consisting of six individual microRNAs,including miR-17,miR-20a,miR-18a,miR-19a,miR-19b and miR-92a-1,is a kind of typical oncogenic polycistron microRNA.MiR-19 (containing miR-19a and miR-19b),as the key oncogenic component in miR-17-92 cluster,is overexpressed in human cancers including lymphomas,leukaemia,lung cancer,breast cancer and multiple myeloma,and has been one of research focus in recent years.It is found that miR-19 promotes tumor growth,invasion and metastasis through negative regulation of target genes such as PTEN,PP2A,Bim,SOCS1,and is correlated strongly with PI3K-AKT-mTOR pathway.MiR-19 plays an important role in tumor genesis and development.

Objective To study the inhibitory effect of knocking down miR-30a-5p on the U87 human glioma xenograft growth and its possible mechanism.Methods Nude mice bearing subcutaneous U87 human glioblastoma were established and separated into three groups (eight for each group) by randomized digital table method,including control group,scr-ODN treated group and AS-miR-30a-5p treated group.After relevant subcutaneous injection treatment,tumor size was measured every other day until the observation period ended.Researchers executed the animals after the treatment,stripped tumor tissues and extracted RNA and protein.Real-time PCR was conducted to detect the expression of miR-30a-5p.The histopathological characteristics and proliferation and apoptosis biological characters (including SEPT7,PCNA,cyclin D1,MMP-2,apoptosis related factor P53,bcl-2 and caspase3) were evaluated by HE and immunohistochemical staining,Westem blot analysis respectively,and the cell apoptosis was detected by TUNEL method.Results In AS-miR-30a-5p treated group,the tumor growth was delayed and the final tumor volume was smaller than that in the control and scr-ODN treated group (F =7.167,P ＜0.05),and the expression of miR-30a-5p was knocked down.The expression of PCNA,cyclin D1 were significantly downregulated while P53,SEPT7 and caspase3 up-regulated.Apoptotic index was increased significantly.Conclusion As-miR-30a-5p suppresses the growth of U87 human gliomas xenografts significantly.Malignant phenotype of tumors are reversed to a considerable degree.Therefore,miR-30a-5p can be a candidate for targeted therapy of human glioma.

This study uses "virtual implant" technology combined with PBL and CBL teaching methods to carry out oral implantology teaching with "restoration as the goal". By instructing students to collect preoperative data and compare actual postoperative data, the continuous cycle verification between problems, objectives, methods, and results is performed. The continuous cycle verification can improve the enthusiasm and initiative of students to learn oral implantology. At the same time, it can allow students to develop the thinking habit of understanding oral implantology with a holistic and whole-process concept and provide strong educational guidance for clinical medical students.

Objective:To investigate the influence of digital light processing (DLP) and computer numerical controlmilling (CNC) on the mechanical behavior of zirconia.Methods:Prepared DLP samples (experimental group, n=52) and CNC samples (control group, n=52) with 12 samples in each group were randomly selected using random number table to measure density, grain size and crystal phase composition. According to the different methods fracture toughness test, the samples were divided into indentation method group (IM) and single-edge-V-notch-beam group (SEVNB), with 30 DLP and 30 CNC samples in IM group, 10 DLP and 10 CNC samples in SEVNB group. The IM group was tested under three different loads (49.03 N, 98.07 N, 196.10 N), there were 10 samples for each load and each sample was tested at 15 points, and the load with the ratio of crack length to indentation diagonal length greater than 2.5 was selected as the indentation load to calculate its IM fracture toughness. At the same time, the SEVNB group was tested with four point bending test to record the maximum load at the time of fracture and calculate the SEVNB fracture toughness. Finally, the indentation and fracture surface were observed using optical microscope and scanning electron microscope, and the results of DLP group and CNC group were further compared to explore the difference in fracture mechanism. Results:The microstructure of DLP and CNC zirconia was basically the same, the density of DLP group was (6.020±0.021) g/cm 3, the grain size was (0.603±0.033) μm; the density of CNC group was (6.038±0.012) g/cm 3, the grain size was (0.591±0.033) μm. Both groups were composed of tetragonal zirconia. The load of 196.10 N was chosen as the indentation load for two groups to calculate the IM fracture toughness. In terms of fracture toughness, there was no significant difference between the two groups ( P>0.05). Scanning electron microscope images of fracture surface showed the intergranular fracture was the leading fracture mode of two groups. The IM and SEVNB fracture toughness of DLP zirconia were (6.111±0.179) MPa·m 1/2 and (7.221±0.809) MPa·m 1/2, respectively. The IM and SEVNB fracture toughness of CNC zirconia were (6.126±0.383) MPa·m 1/2 and (7.408±0.533) MPa·m 1/2, respectively. Conclusions:The microstructure of DLP and CNC zirconia is almost the same, and there is little difference in the fracture toughness of zirconia between two processing technologies.

Objective: To explore the clinical features, the serotype distribution and drug resistance of the isolates in patient with invasive pneumococcal disease (IPD). Methods: By retrieving the laboratory information system in 18 children′s hospitals from 2012 to 2017, the children with IPD were enrolled. Streptococcus pneumoniae (Spn) must be isolated from the sterile sites (blood, cerebrospinal fluid, hydrothorax and joint effusion etc.). The clinical characteristics, serotype, drug resistance, treatment and prognosis were reviewed and analyzed. According to the telephone follow up results, the patients were divided into death group and recovered group. The index as an independent risk factor of mortality was demonstrated by multivariate logistic regression analysis. Results: There were 1 138 children with IPD, including 684 male and 454 female. The proportion of male to female was 1.5∶1. The age ranged from one day to 16 years. The median age was 1 year 3 month. The majority was under 5 years of age (89.3%, n= 1 016), especially under 2 years of age (61.9%, n=704). In all cases, 88.2% (n=1 004) were community acquired infection. The infections included meningitis (n=446, 39.2%), pneumonia with bacteremia (n=339, 29.8%), and bacteremia without focus (n=232, 20.4%). Underlying diseases were found in 242 cases (21.3%). Co-infections were determined in 62 cases (5.4%) with mycoplasma, 27 cases (2.4%) with adenovirus and 34 cases with influenza virus (3.0%). The penicillin insensitivity (PNSP) rates in meningitis and non-meningitis isolates were 69.5% (276/397) and 35.9% (221/615), respectively. There were 81 strains serotyped, in which 93.8% (76/81) were covered by 13-valent protein-polysaccharide conjugate vaccine (PCV13). In the 965 patients who were followed up by phone call, 156 cases (16.2%) were confirmed dead. The independent risk factors for the death were under 2 years of age (OR=2.143, 95%CI 1.284-3.577, P=0.004), meningitis (OR=3.066, 95%CI 1.852-5.074, P<0.01), underlying disease (OR=4.801, 95%CI 2.953-7.804, P<0.01), septic shock(OR=3.542, 95%CI 1.829-6.859, P<0.01), disseminated intravascular coagulation (DIC) (OR=4.150, 95%CI 1.468-11.733, P=0.007), multiple organ failure (OR=12.693, 95%CI 6.623-24.325, P<0.01) and complications of central nervous system (OR=1.975, 95%CI 1.144-3.410, P=0.015). Conclusions Most children with IPD were under 5 years of age, having underlying diseases and acquired the infection in community. The independent risk factors for death were under two years old, meningitis, underlying diseases and multiple organ failure. The problem of drug resistance was severe. The universal immunization of PCV13 would be effective to prevent IPD in Chinese children.