Objective To determine the changes of cerebrospinal fluid(CSF) ?-endorphin(?-EP) and C-reactive protein(CRP) in children with central nervous system(CNS) infection.Methods Sixty-five children suffered from CNS infection were determined the plasma and CSF ?-EP and CRP concentration during the acute and recovering stage with radioimmunoassay, which included 48 viral encephalitis, 12 purulent meningitis and 5 tuberculou meningitis,and 24 non-CNS disease children were as control group.Results The concentrations of plasma and CSF ?-EP of every experimental group were obviously higher than those of control group during the early stage of CNS infection and these were obviously lower during the recovering stage. The serum concentration of CRP during acute stage was significantly higher than that during recovering stage. No change of serum and CSF CRP concentration was determined during either the acute or recovering stage in the other two experimental groups.Conclusions Determining the plasma and CSF ?-EP is mea-(ningful) in early diagnosis of CNS infection,and determining the serum CRP at the same time may be helpful in differentiating septic and inseptic infection.

We established an indirect ELISA method using Trichinella spiralis trehalase(TsTRE)protein expressed in prokaryotic cells.The TsTRE gene was amplified by RT-PCR and ligated into the pCold I plasmid,which was expressed in E.coli BL21 competent cells.The rTsTRE protein was purified through affinity column chromatography.The TsTRE protein was localized with immunofluorescence techniques,and the immunogenicity of rTsTRE was detected by westernblotting.Subse-quently,rTsTRE protein was used as a coating antigen to establish an indirect ELISA.We optimized the antigen-coating con-centration,serum dilution concentration,antigen-coating incubation time,type of blocking solution,blocking incubation time,HRP-labeled goat anti-rabbit IgG serum dilution concentration,HRP-labeled goat anti-rabbit IgG serum incubation time and response time of TMB.Subsequently,the critical value,repeatability,sensitivity,specificity and clinical detection rate of the ELISA were evaluated.Immunofluorescence indicated that trehalase was abundant in the rod-shaped body,tail and epidermis of Trichinella spiralis muscle larvae.Western-blot indicated that rTsTRE protein combined with the positive serum of mice infected with T.spiralis for 42 d;the band was approximately 60 kDa.The established indirect ELISA had a positive threshold of 0.384;the intra-run and inter-run coefficients of variation were 5.504％-7.630％ and 4.664％-9.929％,and did not exceed 10％.The lowest detectable titer was 1:1 280.No cross reaction was observed with antibodies to Clonorchissinensis,Schistosoma ja-ponicum,Ascaris suum,Toxocara gondii and Toxocara canis,and the clinical negative detection rate was 0％.Thus,we suc-cessfully expressed the rTsTRE protein.Moreover,the established indirect ELISA method using the TsTRE protein as the coating antigen had good repeatability,sensitivity,specificity and clinical detectability,and can be applied to the detection of clinical samples.