Objective To evaluate the application effect of‘incorrect cases’in medical statis-tics teaching. Methods The junior students (n=307)of clinical medicine were selected as research subjects by random cluster sampling. They were divided into the teaching improving group (n=151) who accepted case teaching and control group (n=156)who accepted traditional teaching. At the end of the term,the teaching effect was surveyed by questionnaires and compared between the two groups. Measurement data was analyzed by t test,enumeration data by χ2 test and ranked data by rank sum test. Results Students' interests of medical statistics and understanding the importance of the course in teaching improving group were significantly higher than that in control group (Z=-2.375,P=0.018;Z=-2.971,P=0.003). The proportion of students with learning difficulties in teaching improving group was obviously lower than that in control group (Z=-2.488,P=0.013). The satisfaction with theory and practical teaching in teaching improving group (84.10% and 88.74%,respectively)was significantly higher that in control group (73.08%and 71.79%,respectively)(χ2=5.530,P=0.013;χ2=13.841,P<0.001). Although no difference was observed in the test score between the two groups (t=1.230,P=0.220),knowledge of parameter estimation,hypothesis testing and science research design in teach-ing improving group was significantly higher than that in control group (χ2=6.829,P=0.009;χ2=5.835, P=0.016). Conclusions Application of ‘incorrect cases’in medical statistics teaching could arouse students' learning interests and improve clinical medical students' comprehensive analy sis ability of medical statistics.

Objective To evaluate prognostic significance of c-kit and PDGFR-α gene mutation in extragastrointestinal stromal tumors(EGIST). Methods Paraffin embedded tissue specimens from 23 EGISTs were tested for CD117,CD34 and Ki-67 expression by immunohistochemical method.EGIST cases were also tested for the presence of c-kit exons 9,11,13,17 mutations and PDGFR-α exons 12,18 mutations.Kaplan-meier survival rate was used to evaluate the prognostic factors. Results Of 23 cases of EGIST,23(100%)were positive for CD117,17(74%)were positive for CD34.For Ki-67 labeling index(Ki-67 LI):30%were＜1%,44%were between 1%-5%,26%were＞5%.C-kit mutations were detected in 44% of EGIST patients and all were of exon 11 mutations.PDGFR-α mutations were found in 13%of all the 23 cases and all were of exon 18 mutations(The commonest type of mutation D842V).Survival analysis indicated that mitotic count and Ki-67 index were significant predictors for survival.Conclusion The pattern of c-kit and PDGFR-α mutation in EGIST was essentially similar to that in GIST.But the mutation frequency of PDGFR-α was slightly higher in EGIST than in GIST.EGIST could be a special subtype of GIST.The results of this study also show combination of mitotic counts and Ki-67 labeling index may be useful for predicting the prognosis of EGIST.

0. 05) and the specificity is higher than that of the SEA-ELISA (P

AIM: To clone the extracellular domain of N-cadherin cDNA, and to observe the antigenicity of the expressed protein. METHODS: Total RNA was extracted from CD34+ cells separated from fetal liver and bone marrow cells. The extracellular domain of N-cad cDNA was amplified with RT-PCR and inserted into a vector pOPE101-215. The recombinant pOPE-N-cad was expressed with IPTG induction. Then, mice were immunized with the protein. RESULTS: The extracellular domain of N-cad cDNA from CD34+ cells was identified by DNA sequencing. The recombinant pOPE-N-cad in host XL1-blue expressed a 70 kD protein after induced with IPTG, and anti-N-cad antibody was detected in serum of the immunized mice after 5 times injection of the recombinant N-cad protein. CONCLUSION: CD34+ cells bore N-cad gene and the recombinant protein of the extracellular domain of N-cad cDNA shows good immunogenicity.

Objective:To investigate the effects of pre-existing antibody on seroconversion rate after influenza vaccination.Methods:This study recruited 1 900 healthy volunteers to receive influenza split vaccines in Xinjiang Uygur Autonomous region and Yunnan Province from September 2009 to October 2018. Hemagglutinin agglutination inhibition assay was used to detect the titers of specific antibodies in blood samples collected before vaccination and 28 d after vaccination and the effects of pre-existing antibody on the seroconversion to different influenza vaccine components were analyzed.Results:Trend analysis showed that with the increasing titer of pre-existing antibody, the seroconversion rates to A/H1N1, A/H3N2, B/Victoria and B/Yamagata vaccine components were gradually decreased (χ 2=121.76, P<0.001; χ 2=67.58, P<0.001; χ 2=45.25, P<0.001; χ 2=54.55, P<0.001). After adjusting for factors such as region, gender and age, multivariate logistic regression showed that pre-existing antibody titer equal to or higher than 40 was an independent factor that affected the seroconversion to A/H1N1, A/H3N2 and B/Victoria vaccine components, and the adjusted OR (95%CI) values were 2.50(2.00-3.13)、1.64(1.35-2.00) and 2.50(1.79-3.45), respectively. Conclusions:The seroconversion rate to each vaccine component was negatively correlated with the pre-existing antibody titer. The factor that pre-existing antibody titer equal to or higher than 40 was detrimental to the seroconversion to A/H1N1, A/H3N2 and B/Victoria vaccine components, but had no significant influence on B/Yamagata seroconversion.

Data based on the antiviral-resistant phenotyping characteristics of 884 influenza B viruses circulating in mainland China from October 2013 to March 2014 were analyzed to assess the susceptibility of influenza B viruses to neuraminidase inhibitors. All 884 viruses were sensitive to oseltamivir; two viruses (0.23%) had reduced sensitivity to zanamivir and all other viruses were sensitive to zanamivir. Among the 38 viruses with a B/Victoria lineage, B/Shandong-Kuiwen/1195/2014 exhibited a half-maximal inhibitory concentration (IC50) for zanamivir that was elevated by 5. 12-fold (1.78 nM) compared with neuraminidase inhibitors sensitive to the reference virus (0.34 nM), suggesting that it exhibited reduced inhibition by zanamivir. D35G, N59D and S402T (39, 64 and 399 with N2 number) amino-acid substitutions in the NA gene were detected with no previously reported antiviral-resistant substitutions. Among viruses with the 846 B/Yamagata lineage, B/Hunan-Lingling/350/2013 exhibited a 7.99-fold elevated IC50 for zanamivir (2.72 nM) compared with neuraminidase inhibitors sensitive to the reference virus (0.34 nM), suggesting that it exhibited reduced inhibition by zanamivir. D197N (N2 number), a previously reported antiviral resistant-related amino-acid substitution in the NA gene, was detected in B/Hunan-Lingling/350/2013. These data suggest that recently circulating influenza B viruses in mainland China have retained susceptibility to neuraminidase inhibitors.
Amino Acid Substitution ; Antiviral Agents ; pharmacology ; China ; epidemiology ; Drug Resistance, Viral ; Enzyme Inhibitors ; pharmacology ; Humans ; Influenza B virus ; drug effects ; enzymology ; genetics ; isolation & purification ; Influenza, Human ; epidemiology ; virology ; Microbial Sensitivity Tests ; Neuraminidase ; antagonists & inhibitors ; genetics ; metabolism ; Viral Proteins ; antagonists & inhibitors ; genetics ; metabolism

Objective To analyze the phenotypic characteristics of antiviral-resistant influenza B viruses circulating in mainland China and to analyze the susceptibility of influenza B viruses to neuraminidase inhibitors ( NAIs) . Methods Antiviral-resistant phenotyping test was performed to analyze the NAI suscep-tibility of 1 386 influenza B viruses isolated in mainland China from April 2014 to March 2015, including the test of susceptibility to oseltamivir and zanamivir. Results All of the 94 B-Victoria lineage viruses were sensitive to oseltamivir and zanamivir. Of all 1 292 B-Yamagata lineage viruses tested, 1 virus showed re-duced sensitivity to oseltamivir with NA gene containing I221T amino acid mutation, 10 viruses showed re-duced sensitivity to zanamivir with 4 having D197N amino acid mutation in NA gene, 3 viruses showed re-duced sensitivity to both oseltamivir and zanamivir with NA gene possessing D197N amino acid mutation and 1 virus carrying the A245T amino acid mutation in NA gene showed reduced sensitivity to oseltamivir and highly reduced sensitivity to zanamivir. Conclusion The majority of influenza B viruses circulating in main-land China during 2014 to 2015 were sensitive to NAIs, which indicated that NAIs could be used continually for clinical treatment of patients with influenza. Sustained monitoring of antiviral susceptibility of influenza B viruses should be emphasized for timely detection of antiviral resistant viruses and more attention should be paid to the D197N mutations in NA gene of influenza B viruses.

To construct a scFv antibody mini-library by phage display technique from the spleen cells of BALB/c mice immunized with extracellular domain of N-cadherin (N-cad), CD34 and AC133, the extracellular domain genes of N-cad, CD34 and AC133 were cloned into a phagemid pSEX81 respectively, and were then displayed on the phagemid in the form of fusion protein with p III protein. After being effectively immunized with the fusion protein, the spleen of the mice were harvested, and total RNA were extracted from the spleen. The cDNA of VH and VL genes were amplified by RT-PCR, and a scFv-phage display antibody library was constructed with the amplified V-genes. The content, multiplicity and expressing potential of the library were examined. As a result, we had produced a scFv library containing 1.4 x 10(6) individual clones which showed different patterns after being digested with restriction endoneuclease Mua I. The surface display expression of the library was also verified. It indicated that the capacity and diversity of the library was sufficient for screening specific scFv antibody against N-cad, CD34 and AC133. The library will be useful for isolating corresponding specific scFv antibodies.
AC133 Antigen ; Animals ; Antibodies ; genetics ; Antigens, CD ; immunology ; Antigens, CD34 ; immunology ; Base Sequence ; Cadherins ; immunology ; Female ; Glycoproteins ; immunology ; Immunoglobulin Fragments ; biosynthesis ; genetics ; Immunoglobulin Variable Region ; biosynthesis ; genetics ; Mice ; Mice, Inbred BALB C ; Molecular Sequence Data ; Peptide Library ; Peptides ; immunology

To analyze the antigenic and genetic characteristics of the influenza A (H3N2) virus in mainland China during the surveillance year of 2013-2014, the antigenic characteristics of H3N2 virus were analyzed using reference ferret anti-sera. The nucleotide sequences of the viruses were determined by Sanger dideoxy sequencing, phylogenetic trees were constructed with the neighbor-joining method, and the genetic characteristics of the viruses were determined in comparison to current vaccine strains. The results showed that most of the H3N2 viruses were antigenically closely related to the A/Victoria/361/2011 vaccine strain cell-propagated prototype virus (99.6%). Using the A/Texas/50/2012 egg isolate as the reference antigen, 15.1% of the viruses were found to be closely antigenically related to it, while 11.9% of strains were closely antigenically related to the egg-propagated epidemic strain, A/Shanghai-Changning/1507/2012. Phylogenetic analysis of HA genes indicated that the A(H3N2) viruses in this surveillance year were in the same clade, but no drug resistant mutation was identified in the NA genes. During the 2013-2014 influenza surveillance year, no significant genetic change was detected in either the HA or NA genes of the A(H3N2) viruses, while significant mutations were found in egg isolates resulting from their adaptation during propagation in eggs. The antigenic and genetic changes should be investigated in a timely manner to enable the selection of an appropriate vaccine strain in China.
Animals ; Antigenic Variation ; Base Sequence ; Chick Embryo ; China ; Genetic Variation ; Hemagglutinin Glycoproteins, Influenza Virus ; genetics ; immunology ; Humans ; Influenza A Virus, H3N2 Subtype ; genetics ; immunology ; isolation & purification ; Influenza, Human ; virology ; Molecular Sequence Data ; Mutation ; Phylogeny

Objective To determine the incidence and prevalence of transient ischemic attack (TIA) and to evaluate its epidemiological situation in Hunan province.Methods Seven monitoring points were randomly selected from the province,a total of 8 311 subjects aged≥50 years were then chosen by stratified sampling.The cases counted in prevalence was defined as patients diagnosed before 24:00 o'clock August 31st,2013,and the new diagnosis for incident counting was defined as those diagnosed between 00:00 September 1st,2012 and 24:00 August 31st,2013.Results Among all 8 311 screened subjects,the number of TIA patients was 24 (288.8 per 100 000 people),the incidence of TIA was 7 (85.2 per 100 000 people).Standardized prevalence and incidence were 283.2 and 82.4 per 100 000 respectively using 2010 China census population.Among them,the standardized incidence rate of female was higher than that of male (114.8 per 100 000 person-years vs.48.8 per 100 000 person-years),and the prevalence rate of males was higher than that of female (288.2 per 100 000 people vs.273.2 per 100 000 people).Hypertension is the most important risk factor for TIA (55.2％).Conclusion The incidence and prevalence of TIA in Hunan province are higher than the national average.Hypertension is the main risk factor.