Objective To observe the response of the guiding vane to axial flow pump by testing two types of miniature axial flow pump,which have been developed by our group in recent years.Methods Two types of axial flow pump were tested in a mock circulation apparatus.Results The outputs of the two types of miniature axial flow pump all attain 5L/min against the pressure of 13.332kPa,which is enough for left ventricular assistance.The outputs are similarly related to their pre-load and after-load pressure.In this study,the guiding vane does not produce a significant affection on the hydrodynamic characteristic of the axial follow pump.Conclusion The guiding vane may be neglected in the design to improve the blood compatibility of a axial flow pump heart assist device.

Trueperella pyogenes(TP),an important livestock and poultry pathogen,can cause vari-ous diseases such as suppurative pneumonia,arthritis,and mastitis in animals.The newly brought calves of one cattle farm occurred respiratory diseases and accompanied death in Yunyang,Chongqing,based on post-mortem examination,suppuration nodules were found in the lungs,and microscopic observation of tissue smears with staining showed that a lot of short rod shape bacteri-a were in tissue.The bacteria were isolated and purified from the clinic lung tissue and analyzed by 16S rRNA sequence,the result showed the infectious bacteria was Rueperella pyogenes,and it was nominated as TpCQ-yy1.TpCQ-yy1 cultured on rabbit blood agar plates could form double-zone hemolysis,and can utilize glucose and lysine.Interestingly,the drug-resistance characteristics of TpCQ-yy1 partially changed along with the variation of the culture medium.Pathogenicity analysis showed that TpCQ-yy1 could make suppurative lesions in the lungs of mice infected via the thorac-ic and intraperitioneal route,and later led mice to death,while the subcutaneous and intramuscular routes of infection had only suppurative foci at the site of injection and were dose-dependent and non-lethal.The genome size of TpCQ-yy1 is 2.335 Mb,which encoding 2 107 proteins,and the phy-logenetic analysis showed TpCQ-yy1 is close to Trueperella pyogenes TP1 strain but away from other strains.TpCQ-yy1 infection could promote the secretion of inflammatory factors of macro-phage.TpCQ-yy1 inactivated bacterial vaccine and recombinant hemolysin(rPLO)subunit vaccine could induce high levels of antibodies production in mice immunized via subcutaneous and muscle route,but only provided 33.3％-66.7％protection to the immunized mice against TpCQ-yyl infec-tion via intraperitioneal route.This research provides a fundamental basis for the understanding of the biological characteristics,pathogenicity,and prevention and control of Trueperella pyogenes.

Objective To investigate the preventive and inhibitory effects of tumor cell lysate(TCL) combined with IL-2 on melanoma and the potential immune mechanism. Methods The B16F10 melanoma TCL cell were prepared using an ultrasonic disruptor. Twenty-four C57BL/6 mice were randomly divided into four groups which were immunized with PBS, IL-2, TCL and TCL+IL-2 for three weeks, and contra lateral tumors were implanted in the fourth week. We observed onset time of tumor and tumor size, collected peripheral blood continuously and monitored the expression of CD4⁺T and CD8⁺T cell subsets dynamically by flow cytometry. Spleen and tumor tissues of mice were also tested for CD4⁺T and CD8⁺T cell subsets by flow cytometry and immunohistochemistry, respectively. Results The preventive immunization of the TCL+IL-2 group significantly delayed the onset time of tumor (P=0.034); moreover, the tumor volume (P=0.023) and tumor weight (P=0.0015) were also significantly smaller than those in the control group. The expression of CD8⁺T cell subsets in the TCL+IL-2 group and the TCL-only group were significantly higher than that in the control group (P=0.0016, P=0.012). However, the CD4⁺T cell subsets of the TCL+IL-2 group decreased after tumor implantation, compared with the control group (P=0.0089). The expression of CD4⁺T and CD8⁺T cell subsets in spleen and tumor tissues were as same as those in peripheral blood. Conclusion The tumor vaccine of TCL combined with IL-2 could prevent the occurrence of melanoma in mouse and effectively inhibit tumor growth by activating CD8⁺T cells.

infC gene encodes the translation initiation factor IF3 in bovine Pasteuella multocida,but it whether or not regulation to the virulence and cross-protection in P.multocida is still not well understood.In this study,the infC gene mutant(△infC)derived from bovine P.multocida type A strain CQ2 was constructed using by homologous recombination method.Compared with wild strain,the △infC showed significant increasing in biofilm formation,but the capsule produc-tion,virulence and bacterial loading in organs were significant decreased,and the IL-1β secretion of mouse peritoneal macrophage increased.Along with the infC gene deletion,the expression of genes related to capsule synthesis and LPS synthesis and transport were significantly down-regulated,while that of genes related to biofilm synthesis and outer membrane protein were significantly up-regulated.The inactivated vaccines of wild type and mutant were prepared and mice were immu-nized twice then challenged with wild type strains,respectively.The immuno-protection rate of△in fC inactivated vaccine against bovine P.multocida type A,B and F were 100.0％,83.3％and 0.0％,respectively,and the immuno-protection rate that against rabbit type P.multocida was 33.3％.The results indicated that infC gene could affect the virulence of P.multocida by regula-ting the production of capsule and the expressions of virulence related factors,and the deletion of infC gene conferred a certain cross-protection property of strains.This study provided a certain foundation for the development of P.multocida vaccine.