Insulinoma-glucagonoma clone 20 can express at least 6 isoforms in human cells.These isoforms can affect cell apoptosis and proliferation through apoptosis related signaling pathway,such as TRAIL or TNF signaling pathways.Furthermore,insulinoma-glucagonoma clone 20,as a GTP-GDP exchange factor,participates in the transportation of nerve synaptophysins.

Objective To investigate the prevalence of virulence genes(ply, pspA, nanA, lytA, psaA) among Streptococcus pneumoniae recently isolated from clinical patients. Methods The 133 strains were isolated from patients in three teaching hospitals in Chongqing from 2006 to 2008. Polymerase chain reaction was used to screen for virulence genes (ply, pspA, nanA, lytA, psaA). Results The positive rate of lytA, psaA, ply, nanA and pspA in 133 clinical isolates were 94.7%, 85.0%, 82.7%, 84. 2% and 60.2%, respectively. The positive rates of the lytA, psaA, ply, nanA and pspA genes in 87 common serotypes isolates was 100%, 87.4%, 86.2%, 89.7%, 67.8%, respectively. Conclusion The total positive rates of five virulence genes in the 133 clinical strains were high. The positive rates of five genes in the com-mon serotypes isolates were higher than those in the no-common serotypes. These genes are important virulence genes of Streptococcus pneumoniae. They could be candidates for protein vaccine of Streptococcus pneumoniae.

Objective To investigate long-term biological variability of serum lipids in Chinese. Methods Serum lipids in a Chinese population with relatively stable life styles were monitored with standardized measurements for 1 year (specimens were taken bimonthly) (23 subjects) or 10～15 years (yearly) (100 subjects). Results The total intra-individual variability (analytical and biological variations combined) of total cholesterol, triglycerides, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol averaged 10%, 28%, 16% and 18%, respectively. Conclusion Biological intra-individual variability is a major source of inaccuracy of cardiovascular risk assessments based on lipid measurements. Measures need to be taken to minimize biological variation when medical decisions are to be made in the treatment of lipid disorders.

Decreased serum high-density lipoprotein cholesterol (HDL-C) and increased low-density lipoprotein cholesterol (HDL-C) concentrations are important risk factors for cardiovascular diseases. Achieving accurate and comparable HDL-C and LDL-C results is the primary requirement for the prevention and treatment of cardiovascular diseases, in which reference system including reference method, reference materials and standardization programs are needed. The current reference method for HDL-C and LDL-C measurement is the β-quantification method developed by the United States Center for Disease Control and Prevention (CDC), a multi-step procedure involving ultracentrifugation, chemical precipitation, and cholesterol analysis by CDC reference method. This method uses a large amount of serum and is technically demanding which limited its application in standardization. The reduced volume β-quantification method uses a small volume of serum sample, is simple and high through put and is more applicable. However, both methods are sensitive to serum matrix. Commutability of reference materials should be evaluated when they are used to calibrate routine methods. Fresh (non-frozen) serum samples should be used for a split sample comparison between reference and direct methods. In addition, development of reference measurement procedure based on ultracentrifugation and preparation of commutable reference materials are the important work in lipoprotein standardization.

ObjectiveTo investigate the biological variations ( CVI,CVG ) of serum high-density (HDL2-C,HDL3-C ) and low-density (LDLa-C,LDLb-C ) lipoprotein subfractions and high-density lipoprotein cholesterol esterification rates (FERHDL and MERHDL ).MethodsTwenty healthy volunteers,10 males and 10 females,were recruited for this study from September to October,2010.Blood was collected four times from each individual with a 2-week interval between each sampling.Serum lipoprotein subfraction cholesterol levels were measured by ultracentrifugation/HPLC,FERHDL and MERHDL were measured by HPLC.Within-subject ( CVI) and between-subject ( CVG.) biological variations and quality specifications for precision,bias and total error were calculated.Results The average CVI of this group were 5.5％ and 7.2％ for HDL3-C and HDL2-C,11.2％ and 18.7％ for LDLa-C and LDLb-C,11.95％ and 12.3％ for FERHDL and MERHDL,respectively.The CVG for HDL2-C was 45.5％,much higher than that of HDL3-C (8.7％),and FERHDL(49.5％ ) had a higher CVG than MERHDL (30.6％ ).For each analyte,there was a considerable variation of CVIamongindividuals.ConclusionsBiologicalvariationsof lipoprotein subfractions,FERHDI and MERHDL have been estimated.These rsults will play an important role in quality specifications and cardiovascular disease risk assessment.

Objective To establish a method for measuring serum cotinine by isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) and provide an assay that can be applied to theevaluation of the level of smoke exposure and to the risk analysis of smoking related diseases.Methods Blood samples were collected from 94 apparently healthy subjects from October to December in 2010 and centrifuged,and the sera were separated.Serum samples were mixed with [ D3 ] -cotinine ( as the internal standard) and treated with acetonitriles to precipitate protein.After centrifugation,the supernatants were transferred and evaporated under a stream of nitrogen until dryness and reconstituted with mobile phase.Then the residuals were analyzed by LC/MS/MS system with multiple reaction monitor model; the concentration of cotinine were quantified by the isotope internal standard method and the stand curve was employed with a series of calibration.To estimate the precision of the method,five frozen serum pools were repeatedly analyzed in five runs,and every pool was analyzed in triplicate.In addition,the recovery rates were analyzed with the serum sample added with different levels of standard.The stability of cotinine in serum preserved at room temperature,4 ℃ and - 80 ℃,respectively.Finally,the levels of cotinine of 94 healthy subjects were measured to evaluate the distribution of cotinine with different smoke statuses.Results Serum cotinine measured by ID-LC/MS/MS was separated well with few interferences.The correlation coefficients between the peak area ratios and cotinine concentrations were higher than 0.9993.The values of within-run coefficients of variation (CV) of five frozen serum pools (0.68,48.42,94.34,250.95 and 287.04 μg/L) were 2.19％,0.78％,0.75％,0.65％ and 0.67％,respectively.The values of total CV were 4.71％,1.40％,1.98％,1.10％ and 1.03％,respectively.The limit of detection (LOD) and limit of quantitation ( LOQ ) were 0.013 and 0.050 μg/L,respectively.The analytical recoveries ranged from 99.22％ to 102.67％.The samples could maintain stability within 2 d at room temperature,7 d at 4 ℃ and 3 months at -80 ℃ resulting the accuracy of measurements from 99.28％ to 100.87％ and the CV＜5％.The levels of cotinine of 94 healthy subjects were measured and shown skewed and leptokurtic distribution.The concentrations of twenty smokers,fourteen former smokers and sixty non-smokers were 116.40 (63.17 -241.12),0.67 (0.15 - 0.95 ) and 0.22 (0.15 - 0.42 ) μg/L,respectively.Furthermore,the level of cotinine of former smokers (Z =-2.12,P ＜0.05) and smokers (Z =-6.67,P ＜0.001) were statistically higher than non-smokers.Conclusions An ID-LC/MS/MS method for serum cotinine detection has been established.It is hoped that the method will be applied to the assessment of smoke exposure and its association with the risks of smoking related diseases since it is simple,specific,precise,sensitive and accurate.

Objective To examine the stability of high-density lipoprotein cholesterol (HDL-C)during serum incubation at different temperature and time periods.Methods Ten healthy volunteers (4 males and 6 females,aged 24 to 59 years)from Beijing Hospital were recruited in May 2015.Fasting venous blood samples were collected and centrifuged to separate the sera.Serum samples were incubated at 4℃ for 24 h,25℃for 0,1,8 and 24 h (with or without an LCAT inhibitor).Serum to-tal cholesterol (TC),total free cholesterol (TFC)HDL-C and HDL-FC were measured by the HPLC Method.Results HDL-FC and HDL-C changed -6.91% and -2.17% during serum incubation at 4℃for 24h.TFC,HDL-FC and HDL-C changed significantly (averaged -13.70%,-25.88% and -1.53% respectively)during serum incubation at 25℃ for 24 h,in which the decrease of TFC and HDL-FC were inhibited by the addition of the LCAT inhibitor.The decrease of HDL-C was even higher in the presence of the LCAT inhibitor.Conclusion Serum TFC,HDL-C and HDL-FC levels changed during serum incubations,which were caused by the LCAT and CETP activities and the transfer of cholesterol among lipoproteins. For accurate measurement of serum HDL-C,prolonged serum storage should be avoided in clinical laboratories.

Objective To explore the sensitivity and specificity of near-infrared spectroscopy ( NIRS) in the diagnosis of depression. Methods From March 2013 to August 2013,62 patients with de-pression and 70 normal controls were collected from Peking University Sixth Hospital. Optical Tomography System (52 channels) was used to collect the NIRS data during the Verbal Fluency Test (VFT),and the number of words produced during VFT task was recorded. The wave analysis was performed by a professional psychiatrist. Results There was statistical difference in the number of words produced during VFT task be-tween the patients with depression (8.65±0.49)and control group(10.19±0.43) ( t=2.385, P<0.05). Through the wave analysis of NIRS to test patients with depression,the results demonstrated that the sensitivi-ty was 66.1% and the specificity was 91.4%. Conclusion The results of NIRS test display high specificity in the diagnosis of depression,which can be used as an objective index for clinical auxiliary diagnosis.

Objective To explore the effects of emotion on cognitive function in patients with depression.Methods Self-rating anxiety scale(SAS),self-rating depression scale (SDS) and the typical one-back task were done by 397 patients with depression in Peking University Sixth hospital out-patient and hospitalization during 2012 June to 2013 October.Results Both of the SAS standard score (51.81 ± 11.50) and SDS standard score (62.94 ± 13.06) were significantly related (r=0.125,P＜0.05.r=0.176,P＜0.01) to the reaction time of one-back task ((590.27±213.96)ms),and the correlation between SAS standard score and SDS standard score was significant (r=0.682,P＜0.01).The results of regression analysis suggested that,only SDS score could predict the reaction time of one-back task.Conclusion The emotion of anxiety and depression in patients with depression are correlated with cognitive function,and the emotion of depression is the main factor to affect the cognitive function.