Aim To construct the cell model targeted on the damage by α-synuclein for screening anti-Parkinson’s Disease (PD)compounds.Methods The cDNA fragment of α-synucle-in gene was obtained by PCR methods and inserted into the re-combinant prokaryotic plasmid by molecular cloning technique. The recombinant plasmid was transformed into Escherichia coli, and subsequently induced to express α-synuclein protein.The recombinant α-synuclein was purified and identified by affinity chromatography,immunoblotting and mass spectrometry.The cells damage by α-synuclein was evaluated through cell viability measured by 3-(4,5-dimethyl-2-thiazolyl )-2,5-diphenyl-2-H-tetrazolium bromide.Results The obtained cDNA fragment ofα-synuclein in accordance with its theoretic molecular weight was cloned into pET30a plasmid and verified by sequencing.The re-combinant plasmid was transformed into bacteria E.Coli.BL21 (DE3)and induced to express α-synuclein by isopropyl β-D-1 -thiogalactopyranoside (IPTG).The expression condition was op-timized according to the culture temperature,the concentration of IPTG and the proliferation state of bacteria.The purified α-synu-clein was proved to be a 1 5.3 ku molecule weight protein,and could be immunoblotted with anti-α-synuclein antibody.The pu-rified α-synuclein could decrease the viability of PC1 2 cells and primary neurons significantly,and its effect was in a concentra-tion-dependent manner.Conclusion We have succeeded in constructing the cell model targeted on the damage by α-synucle-in.

Objective To explore the application value of serum procalcitonin(PCT)quantitative detection in diagnosing pediat-ric bloodstream infection.Methods The results of 183 cases of blood culture and simultaneous PCT detection in a hospital from February to November 2013 were analyzed retrospectively.The patients were divided into the non-bloodstream infection group and the bloodstream infection group according to the blood culture results as the golden standard.The differences of serum PCT concen-tration were compared between the two groups by the Mann-Whitney U test.Results The serum PCT concentration was 0.15 (0.065-0.55)ng/mL in the non-bloodstream infection group and 1.11(0.505-8.975)ng/mL in the bloodstream infection group, the difference was statistically significant(P =0.000);with 0.50ng/mL as the cut-off value of diagnosis,the sensitivity and the spe-cificity of PCT was 77.8% and 73.3% respectively,the positive and pegative predictive value of PCT was 24.1% and 96.8% re-spectively.Conclusion The quantitative detection of PCT can assist in rapidly diagnosing or excluding bloodstream infection and provides reference for avoiding the overuse of antibiotics or conducting the early anti-infection therapy.