Objective To investigate the effects of silencing of the human cerebral 21 .5 kDa myelin basic protein (MBP) gene on the proliferation and apoptosis of the glioma U251 cells .Methods The 21 .5 kDa MBP sequence‐specific short hair‐pin RNA (shR‐NA) recombinant plasmids pGenesil‐1‐MBP‐3 were transfected into the human glioma cell line(U251) ,the cells of U251 was used as MBP silencing group ,the cells transfected with negative control plasmids used as negative control group ,and the cells transfected with liposomes used as blank control group .Real‐time PCR and Westernblot were used to detect the expression levels of the 21 .5 kDa MBP mRNA and protein in each group ,and the cell proliferation curve was measured by CCK‐8 assay ,the apoptosis rate was a‐nalysised by Flow cytometry .Results Both the mRNA and the protein expression levels of the 21 .5 kDa MBP of MBP silencing group were significantly lower than those in the control groups (P<0 .05);the cellular proliferation activity of the MBP silencing group decreased significantly (P<0 .05)while the cellular apoptotic rate increased significantly (P<0 .05) .Conclusion Silencing of the human cerebral 21 .5 kDa MBP gene may playa dual role in the inhibition of proliferation and the promotion of apoptosis of the glioma U251 cells .

Objective To establish a cellular model for the expression of the C-type lectin dendritic cellspecific intercellular adhesion molecule-3-grabbing non-integrin (DC-SIGN),and to provide a basis for the functional analysis of DC-SIGN.Methods The cDNA of DC-SIGN was obtained via PCR,and cloned into the eukaryotic expression vector porcine cytomegalovirus-enhanced green fluorescent protein (PCMV-EGFP) with EGFP at the N terminal of DC-SIGN.Then,the recombinant PCMV-EGFP-DC-SIGN plasmid was transfected into HEK293T cells followed by the detection of DC-SIGN expression using PCR,Western blot and flow cytometry.Confocal microscopy was performed to localize the expression of DC-SIGN-EGFP and visualize the recognization and internalization of the Derp2 allergen by DC-SIGN.Results The recombinant fluorescent fusion protein-expressing plasmid was successfully constructed.Both PCR and Western blot confirmed the expression of DC-SIGN.Flow cytometry showed that the expression of DC-SIGN was increased by approximately 50％ in HEK293T cells transfected with the recombinant expression plasmid compared with those untransfected.As confocal microscopy showed,the green fluorescence-labelled DC-SIGN was located on the cell membrane,which could bind to the red fluorescence-labelled antigen Derp2 and internalize it into the cells.Conclusions The recombinant DC-SIGN-EGFP fusion protein is characteristically located on the surface of 293T cells,which can be recognized by the DC-SIGN-specific antibody and is capable of internalizing the allergen Derp2,and may serve as an ideal cell model for further studies on molecular function of DC-SIGN.

Objective To synthesize herpes simplex virus (HSV) envelope glycoprotein gC using gene engineering techniques,and to verify its expression.Methods Two separate parts of the HSV envelope glycoprotein gC,i.e.,GC-F and GC-R,were respectively synthesized.The GC-F and GC-R genes were synthesized,subcloned into the expression vectors pSumo-Mut (containing recognition sequences for endonucleases Stu1 and XhoI) and pCzn1 (containing recognition sequences for endonucleases NdeI and XhoI) respectively to form the recombinant plasmids pSumo-Mut-GC-F and pCzn1-GC-R.E.coli BL21 Arctic Express (DE3) cells were transformed with the two recombinant plasmids separately.Isopropyl thiogalactoside (IPTG) was used to induce the expression of target protein which was subsequently purified by nickel affinity chromatography.Finally,Western blot was performed to verify the reactivity of the synthesized protein with the sera of HSV-1-positive patients.Results Both GC-F and GC-R genes were synthesized by a total gene synthesis method.As sodium dodecyl sulfate polyacrylamide gel electropheresis (SDS-PAGE) showed,the fusion proteins were mainly distributed in the sediment layer.The purity of GC-F and GC-R proteins was over 80％ after purification by affinity chromatography.Western blot showed that both of the proteins were reactive with anti-HSV-1 antibody-positive sera.Conclusions Fusion expression vectors have been constructed for the gC protein,and IPTG successfully induces its expression.Moreover,the resulting proteins could react with anti-HSV-1 antibody-positive sera,and may serve as an ideal experimental material for next functional study.

Objective To study the diagnostic value of magnetic resonance imaging (MRI) and spiral CT in thyroid microcarcinoma (TMC), in order to improve the diagnostic accuracy of TMC. Methods The preoperative imaging manifestations of MRI and spiral CT in 68 TMC patients who were confirmed by surgical pathology were retrospectively analyzed, and the diagnostic accordance rates were compared between the independent and the combined diagnosis. Results The diagnostic accordance rates of MRI and spiral CT in TMC were 73.53%(50/68) and 66.18%(45/68). The diagnostic accordance of combined MRI and spiral CT in TMC was 88.24%(60/68). The diagnostic accordance rate of combined MRI and spiral CT was significantly higher than that of independent examine, and there was statistical difference (P<0.05). The lesion detection rate of MRI was significantly higher than that of spiral CT:95.59% (65/68) vs. 83.82% (57/68), but the calcification lesion detection rate of spiral CT was significantly higher than that of MRI: 85.42% (41/48) vs. 4.17% (2/48), and there were statistical differences (P<0.05 or <0.01). There were no statistical differences in the detection rates of irregular shape lesions, boundary indistinct/coarse lesion, signal/uneven density lesions and cervical lymph node metastasis between MRI and spiral CT (P>0.05). Conclusions Spiral CT is superior to MRI in the micro-calcification detection, and MRI, with a high resolution of soft tissue, can display the lesions of surrounding tissue organs and neck lymph node metastasis better. The combined examine can increase the diagnostic accuracy of TMC.

BACKGROUND: Cellulose is natural material, which has good chemical stability and biocompatibility. The modified material from cellulose has new properties besides its inherent properties.OBJECTIVE: Based on cytocompatibility evaluation tests, this study is designed to evaluate the cytocompatibiUty of materials synthesized from cellulose to make sure its reliability.DESIGN: Contrast study.SETTING: Department of High Polymer, Material Science and Engineering College, Beijing University of Technology.MATERIALS: This study was performed in the Material Science and Engineering College, Beijing University of Technology between March 2003 and June 2004. The material from cellulose prepared by Beijing University of Technology was white, granules, no taste, and no volatilization (density: 1.2 g/cm3, pH: 6-7). L-929 vigorous cells were provided by Chinese Military Academy of Medical Science. Ten male New Zealand rabbits were provided by Animal Center of Chinese Military Academy of Medical Science.METHODS: Based on GB/T16175-1996 standard, cytotoxicity of the materials from cellulose on L-929 cells was evaluated by growth suppression technique (MTr chromatometry). In addition, based on GB-T14233.2-1993 standard, hemolysis in vitro was evaluated through measuring erythrocyte lysis and ferrohemoglobin freeing degree with indirect contact method.MAIN OUTCOME MEASURES: Cytotoxicity test and hemolysis test.RESULTS: Cytotoxicity test showed that the materials from cellulose did not have obvious toxicity on L-929 cells, and the cytotoxicity graduation of the materials from cellulose was 1 or 0. Hemolysis test suggested that the materials from cellulose did not have obvious hemolysis reaction, and the hemolysis rate in vitro was 1.5 %, which was less than the national standard (5%).CONCLUSION: The materials from cellulose do not have obvious cytotoxicity but have great cytocompatibility.

Objective To investigate the different radioprotective effects of total flavonoids of Astragalus (TFA) on human normal mesenchymal stem cells(hMSCs) and hepatoma cells injured by 60 Coγ-ray radiation.Methods hMSCs and HepG-2 cells were cultured and randomly divided into TFA-treated and untreated groups.The cells of different groups were irradiated with 60 Co γ-rays at the dose of 6 Gy.MTT method was utilized to detect the survival rates of the hMSCs and HepG-2 cells pretreated or untreated with TFA before irradiation.Cell clone formation test was used to measure the cellular radiosensitivity.The apoptosis rates of different groups were determined by flow cytometer assay.The expression rates of the apoptosis-promoting proteins Fas and Bax and the apoptosis-inhibiting protein Bcl-2 were analyzed by Western blotting.Results MTT showed that the survival rates of hMSCs pretreated by TFA were 1.15-1.95 times higher than that of the pure irradiation group.On the contrary,the survival rates of the TFA pretreated HepG-2 cells were only 0.53-0.23 times that of the pure irradiation group.There was a good dose-effect relationship between the cell survival rate and the TFA concentration.Cell clone formation rate indicated that combined treatment of TFA and radiation inhibited the cell proliferation more effectively than single TFA or pure radiation.Flow cytometry showed that 6,24 and,48 h post-irradiation to 6 Gy,the apoptosis rates of the hMSCs were 23.3% ,11.2% ,and 2.9% ,respectively in the TFA pretreated group and were 29.3% ,24.9% ,and 13.6% in the pure radiation group.However,the apoptosis rates of the HepG-2 cells at 6,24,and 48 h post-irradiation to 6 Gy were 11.6% ,17.3% ,and 20.1% ,respectively in the TFA pretreated group and were 6.9% ,9.3% ,and 15.8% ,respectively in the direct radiation group.Western blotting showed that the expression levels of Fas and Bax proteins in the HepG-2 cells were significantly higher in the TFA pretreated group than in the pure radiation group.On the contrary,the expression level of the apoptosis inhibiting protein Bcl-2 was significantly lower in the TFA pretreated group than in the pure radiation group.Conclusions TFA has obvious effects of radiological protection on human hMSCs and has no effects of radiological protection but effects of apoptosis enhancement on hepatoma cells.The promotion of apoptosis of TFA on hepatoma cells is primarily through increasing the expression of apoptotic proteins such as Fas and Bax and reducing the expression of anti-apoptotic protein Bcl-2.