Effects of PVA-H Coating Thickness and Tip Angle on Tissue Injury / 医用生物力学

Objective To study the effects of PVA-H coating thickness and tip angle on the tissue injury caused by the implantation of neural electrodes. Methods Simulated implantation experiments were conducted based on a tissue injury evaluation system to evaluate the tissue injury caused by electrode implantation. The coating thicknesses were controlled by the number of dip coating times (0, 1, 2, and 3), whereas the tip angles were set as 30°, 40°, and 50°. The maximum tissue strain and insertion force were selected as the measurement of the tissue injury. Results thicker hydrogel coating and larger tip angle would cause more serious tissue injury. Simultaneously, reducing the tip angle of the neural electrode could reduce the degree of the hydrogel coating effect on the tissue injury. When the tip angle was 30°, the maximum strain and the peak insertion force increased by 3.4% and 3.8%, respectively, whereas when the wedge angle was 60°, the maximum strain and maximum insertion force increased by 11.3% and 18.1%, respectively. Conclusions The hydrogel coating of the neural electrode increased the injury of biological tissues caused by the implantation of the neural electrode. However, the method of decreasing the tip angle of the electrode could reduce the degree of the negative effects of the hydrogel coating thickness on the implantation injury.

Expression of human Streptococcus suis 2 muramidase released protein and preparation and application of its monoclonal antibodies / 中国兽医学报

The mrp gene of SS2 human strain Habb was truncated and cloned into a prokaryotic expression vector pGEX4T-2,and a fusion-expressed protein MRP-GST of 61 000 was obtained in E.coli.The GST was cut from MRP-GST with thrombin protease to gain the purified MRP of 35 000 which showed a strong reaction to the SS2 positive sera in Western blotting.BALB/c mice were immunitied intraperitoneally with purified MRP protein.Murine myeloma cells were fused with the splenocytes of the immunized mice after the third immunization.An indirect ELISA coated with purified MRP was used to screen hybridomas for production of specific antibody.The six McAb recognized MRP specially.According to the results of 71 standard strains (48 SS and 34 SS2)by Sandwich ELISA,the coincidence rate was 97.2%,but for 34 SS standard serotype was 100 %.The ELISA method has a potential value for clinical and epidemiological applicationgs.

Establishment of Epstein-Barr virus-transformed B cell lines from healthy volunteers of type B / 医学研究生学报

Objective: To develop Epstein-Barr virus(EBV)-transformed human peripheral blood B cell lines from healthy volunteers of type B.Methods: B lymphocytes from healthy volunteers of type B capable of producing anti-A antibodies were transformed by EBV,while Cyclosporine A(CsA),as an immunosuppressive agent that could selectively inhibit T-lymphocytes and protect B-lymphocytes from regression,was used in the experiment.Then,the supernanant of the cell culture medium was tested with red blood cells of type A,B and O by agglutinin assay.Results: Twelve of the15 EBV-transformed B lymphocyte cell lines were established,with a success rate of 80%,while 9 human B lymphocyte lines secreted anti-A antibodies.Conclusion: Human B lymphocyte lines secreting antibodies to A antigens were successfully developed,which helps further studies of human blood specific monoclonal antibodies.

Cloning and expression of human anti-Rh(D) single-chain Fv fragment / 医学研究生学报

Objective: To construct a phage display library of human single-chain Fv antibodies against blood group Rh(D) substance. Methods: Combining phage display library techniques, isolated total RNA from B lymphoblastoid cell lines secreting anti-Rh(D) antibodies was used for the synthesis of the first strand of cDNA, V_ H and V_ L genes were amplified by 2nd PCR and linked together by splicing overlap extension (SOE) with the use of a (Gly_ 4Ser)_ 3 linker. The resulted scFv genes were then cloned into pCANTAB5E vectors and displayed on the phage. Phage clones were selected using intact red cells as a source of antigen. After 4 rounds of "binding-elution-enrichment", each clone was assayed for specificity by Dot ELISA. Results: A phage antibody library, with the sink size being 1.2?107, was obtained. The percentage of full-length scFv gene inserted into phage DNA was 0.80. Rescued by helper phage, a phage scFv library with titer of 3?108 pfu/ml was established. Specific phages with scFv were acquired after 4 rounds of panning, one clone exhibiting specific binding to Rh+ cell was identified by Dot ELISA. Conclusion: A strategy for construction phage antibody library by means of phage display technique was practicable, which would be useful in screening engineered antibodies against human Rh (D) blood group substances.

Biological and pathophysiological properties of streptococcal superantigens / 医学研究生学报

Streptococcal superantigens play an important role in many human diseases.In this paper,we mainly discuss the progress in the researches on streptococcal superantigens in such aspects as their structures,biological and pathophysiological properties,expression regulation,and their significance in the management of tumors.

STUDY ON DETECTION OF HEMORRHAGIC FEVER WITH RENAL SYDNROME VIRUS GENE BY DIG LABELED PROBE / 中国人兽共患病学报

Dig-DNA probes of hemorrhagic fever with renal syndrome vinus M S gene fragment were prepared by PCR and random primer labeling, The probes had speciality to HFRSV-RNA and could detect 10pg RNA by RNA-DNA dot-blot hybridization. The results of hybridization showed that positive reactions were found in 5, 10 chigger mites groups from antigenic positive rats, 10 mites group from antigenic negative rats, 10, 50 free chigger mites, and hung of antigenic positive mice 100mg, 500mg. But negative reation in 5 mites group from antigenic negative mice.