Comparison of prediction performance of PAHs carcinogenicity between a BALB/c-E6E7 cell transformation assay and a BALB/c 3T3 cell transformation assay / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To predict the carcinogenicity of polycyclic aromatic hydrocarbons (PAHs) by cell transformation assay using BALB/c 3T3 cells and HPV16-E6E7-transfected BALB/c 3T3 cells (BALB/c-E6E7 cells).</p><p><b>METHODS</b>The cell transformation assays induced by PAHs using BALB-E6E7 cells and BALB/c 3T3 cells.</p><p><b>RESULTS</b>The initiating and promoting activities of PAHs examined in a BALB-E6E7 cell transformation assay were similar to in a BALB/c 3T3 cell transformation assay, which was up to the standard of agents classified by the IARC. There were much more transformed foci appeared and much shorter time consumed to accomplish phenotypic alterations in the BALB/c-E6E7 cell transformation assay than in the BALB/c 3T3 cell transformation assay. The BALB/c-E6E7 cell transformation assay was superior to the BALB/c 3T3 cell transformation assay in cost and labor performance, the sensitivity of transformation response.</p><p><b>CONCLUSION</b>The BALB/c-E6E7 cell transformation assay, with a satisfied prediction performance of initiating activity and promoting activity, would improve the overall process of safety and risk assessment of carcinogenicity.</p>

Pretreatment methods of urine proteomics in children with primary nephrotic syndrome / 中国当代儿科杂志

<p><b>OBJECTIVE</b>To optimize a pretreatment method of urine proteomics in children with primary nephrotic syndrome.</p><p><b>METHODS</b>Urine from children with primary nephrotic syndrome was treated in different pH and isolated by cold acetone precipitation for different durations. Then the amounts and kinds of proteins were compared by quantify, SDS-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional electrophoresis (2-DE) in order to optimize a way to deal with urine protein.</p><p><b>RESULTS</b>Most proteins were obtained at pH 2.7. The amounts of protein precipitated by acetone for 0.5 hr was obviously less than those precipitated for 1 and 2 hrs (P<0.05), while there was no significant difference between the amount of protein precipitated for 1 and for 2 hrs. Protein precipitated by cold acetone for 1 hr at pH 2.7 was selected as the best pretreatment method. Satisfactory 2-DE maps can be acquired.</p><p><b>CONCLUSIONS</b>Urine protein can be best obtained at pH 2.7 and precipitated by cold acetone for 1 hr.</p>

Experimental research on anti-respiratory syncytial virus effect in vitro of earthworm coelomic fluid / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To explore the antivirus function in vitro of earthworm coelomic fluid (ECF) by researching its effect on inhibiting respiratory syncytial virus (RSV).</p><p><b>METHODS</b>By the method of Hep-2 cell culture and using ribavirin as a positive control, the anti-RSV effect of ECF was investigated by observing cytopathic effect (CPE) with MTT colorimetric assay.</p><p><b>RESULTS</b>In Hep-2 cells, the CC50 of ECF and ribavirin were 3.11 mg/ml and 1.35 mg/ml separately. In the experiment of ECF directly killing RSV, the IC50 of ECF was 184.1 microg/ml, SI was 16.87; In the experiment of ECF preventing RSV invasion, no antiviral function of ECF within the experimental concentration range was observed; In the experiment of ECF inhibiting RSV replication, the IC50 of ECF was 1555. 8 microg/ml, SI was 1.99.</p><p><b>CONCLUSION</b>ECF couldn't prevent virus from invading into host cell, but showed direct killing-virus function and inhibition of the virus replication.</p>

Study on antineoplastic effect of earthworm coelomic fluid in vitro / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To explore the antineoplastic effect in vitro of earthworm coelomic fluid (ECF)on growth inhibition and its mechanism for the tumor cell lines Siha, SW480, Colo205 and PC12.</p><p><b>METHODS</b>MTT colorimetric assay, flow cytometry and morphological analysis were used to test its antitumor activity on tumor cell lines and normal cell line Cos7 in vitro.</p><p><b>RESULTS</b>ECF can inhibit the cell growth of Siha, SW480, Colo205, PC12 and Cos7. But different tumor cell lines showed different sensitivity.</p><p><b>CONCLUSION</b>EFC can significantly inhibit the proliferation of tumor cells in vitro by inducing tumor cells apoptosis.</p>

Application of 293 cells in in vitro detection of carcinogens / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To investigate the application of 293 cells to detect suspected carcinogens and provide experimental evidence by using in vitro cell transformation assay and tumorigenicity study.</p><p><b>METHODS</b>The transformation systems of cells cultured in vitro have been adopted to clarify the tumor promotive activity of Microcystin LR (MC-LR). The malignant transformation of 293 cells induced by MC-LR is tested by several methods including clone forming in soft agarose, serum requirement assay and tumor forming in mice to define the promotive activity of 293 cells.</p><p><b>RESULTS</b>293 cell acted like tumor cells after induced by MC-LR: serum dependence decreased, anchorage independence growth in soft agarose and formed cell clones, malignant tumors appeared in SCID mice.</p><p><b>CONCLUSION</b>293 cells were easy to culture and sensitive to environmental carcinogens so that can be used in detection of suspicious carcinogens.</p>

Optimization of human anti-HBsAg scFv secretary expression in Escherichia coli / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To explore the conditions for high expression of anti-HBsAg scFv A-15 in E. coli, increase the production of the scFv in the culture medium.</p><p><b>METHODS</b>By changing induction occasion, concentration of inductor IPTG and induction time, influence of various conditions on expression of anti-HBsAg scFv A-15 was analyzed through ELISA. In addition, the effects of sucrose, glycine and Triton X-100 at different concentrations on the scFv excretion into culture medium was evaluation.</p><p><b>RESULTS</b>The optimal expression conditions were as follows: the induction was started after culturing for 4 h, the concentration of IPTG was 0.5 mmol/L, and the induction lasted for 8 h. The scFv affinity in culture medium with 0.3 mol/L sucrose, 2% glycine, 1% Triton X-100, 16.78-fold higher, respectively than that without the three chemicals. The final yield of anti-HBsAg scFv A-15 was estimated to be 7.4 mg/L.</p><p><b>CONCLUSION</b>The conditions for production of anti-HBsAg scFv A-15 were optimized, which provides a practical method for more efficient production of the scFv in E. coli for further studying structure and function.</p>

An improved BALB/c 3T3 cell transformation assay and its application in the cocarcinogenesis study / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To improve the protocol of BALB/c 3T3 cell transformation assay, and apply it to the cocarcinogenesis study.</p><p><b>METHOD</b>Appropriate serum concentration, culture media and method of administration were selected by testing their effects on the growth and transformation of BALB/c 3T3 cells. The co-carcinogenic activity between diethylnitrosamine (DEN) and microcystin-LR (MC-LR) or 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) were examined using the improved cell transformation assay. The malignant characteristics of transformed cells were verified by neoplasia in SCID mice.</p><p><b>RESULTS</b>There were strong co-carcinogenic activity between DEN and TCDD. On the contrary, although MC-LR has strong ability to induce cell transformation, the effect was markely inhibited by DEN. The transformed cells show some malignant characteristics.</p><p><b>CONCLUSION</b>The improved BALB/c 3T3 cell transformation assay is reliable and time-saving, and can be efficiently used in the study of cocarcinogenesis.</p>