Impact of reattaching various Aeromonas salmonicida A-layer proteins on vaccine efficacy in Atlantic cod (Gadus morhua)

Atypical Aeromonas salmonicida causes atypical furunculosis in a whole range of farmed fish species. The bacterium comprises a heterogeneous group differing in surface components such as the A-layer protein and O-chain polysaccharide structures. Previously, the A-layer protein was shown to contribute to protective immunity as a vaccine with A. salmonicida cells with reattached A-layer protein protecting significantly better than the corresponding A-layer deficient bacteria used in the Atlantic cod (Gadus morhua) vaccine. In the present study, genetically different A. salmonicida A-proteins, either as preformed A-layer sheets from culture supernatants or as purified preparations, were shown to attach to A-layer deficient isolates with a different O-chain structure. Only vaccines containing A. salmonicida cells with reattached A-protein genetically homologous to the challenge isolate, elicited protection comparable to that of the homologous vaccine.     

树舌多糖对心血管系统作用的研究

本文研究了树舌多糖(GAPS)对心血管系统的作用,结果表明:对离体蛙心,GAPS有明显的抑制心肌收缩力和减慢心率作用;对家兔血压有降压作用,此作用可能是其对心脏抑制作用的结果;对垂体后叶素引起家兔心电图中T波抬高有明显的拮抗作用,但对正常家兔心电图无明显影响。从而说明GAPS有增加心肌供血供氧和降低心肌耗氧的作用,可作为治疗冠心病药物试用于临床。     

Biofilm: the microbial “bunker” for intravascular catheter-related infection

Catheter-related infection in cancer patients remains an important health-care problem with major financial implications. During the last few years a better understanding of the pathogenesis of catheter-related infections and the interaction between microorganisms and catheter surfaces has emerged. Recently the influence of biofilm formation in catheter-related infections has been established. The development of biofilm by the colonizing microbes permits attachment of the organisms to the vascular access device and confers resistance to antibiotics and host defense mechanisms. Strategies to overcome the development of biofilm are being developed to prevent catheter- and other medical device-related infections.     

Hemostatic effects of Microporous Polysaccharide Hemosphere® in a rat model with severe femoral artery bleeding

An appropriate hemostatic dressing for prehospital use should lower mortality due to uncontrolled hemorrhage. In this study, the investigators explored the hemostatic effects of Microporous Polysaccharide Hemosphere (MPH) applied in a rat model with severe femoral artery bleeding. Twelve rats were randomly assigned to MPH and control groups: The femoral artery of each rat was pierced to initiate bleeding. Then, 0.25 g MPH was poured into the bleeding site. A 200-g scale weight was placed over the bleeding site for 30 sec. At 30-sec intervals, the scale weight was removed, and hemostasis was assessed visually. After 30 sec, if the bleeding had ceased, the test was scored and checked as "passed at 30 sec." If the bleeding had not stopped, the same procedures were repeated a maximum of 3 times. If hemostasis could not be achieved even after the third application, the test was scored as failed. The same sequence of procedures was repeated for the control group without use of MPH and with only standard compression. Application of MPH resulted in complete control of bleeding in 2 of 6, 4 of 6, and 6 of 6 rats at 30, 60, and 90 sec, respectively. In the control group, however, hemostasis could not be achieved in all 6 rats, even at 90 sec. The difference between the 2 groups was statistically significant (P=.007). Application of MPH and compression with a scale weight significantly decreased the time of hemostasis in the rat model with femoral arterial bleeding.     

Mitigating base-catalysed degradation of periodate-oxidized capsular polysaccharides: Conjugation by reductive amination in acidic media

Reductive amination coupling an aldehyde-containing polysaccharide, generated by periodate oxidation, with the amino groups in protein has been widely used in the synthesis of glycoconjugate vaccines. The conjugation is often achieved under slightly basic conditions via a Schiff’s base intermediate followed by its reduction with sodium cyanoborohydride. We observed that oxidized capsular polysaccharides such as Streptococcus pneumoniae type 6B (Pn-6B) and Haemophilus influenzae type a (HiA) underwent significant degradation during the conjugation in slightly basic media leading to sub-optimal glycoconjugates. Further study on oxidized Pn-3, Pn-6A, Pn-6C, Pn-2 polysaccharides and dextran provided evidence that the degradation is a result of base-catalysed β-elimination. In contrast to HiA, Pn-2, Pn-3, Pn-6B polysaccharides and dextran, oxidized Pn-6A and Pn-6C polysaccharides were stable under basic conditions due to lack of the leaving group at the β-position of the aldehyde. By performing conjugation of oxidized polysaccharides to bovine serum albumin (BSA) in phosphate buffer at pH 6.0, 6.8, 7.2 and 8.0, we concluded that the reductive amination proceeds best in slightly acidic media, particularly with those β-elimination susceptible polysaccharides.     

山药多糖对实验性糖尿病小鼠的治疗及预防作用

目的:研究山药多糖对实验性糖尿病小鼠的预防及治疗作用.方法:建立实验性糖尿病小鼠模型,观察山药对四氧嘧啶糖尿病小鼠血糖的影响,观察预防给药对四氧嘧啶引起的小鼠血糖升高的影响.结果:治疗作用研究表明各剂量组与模型组比较,在降低糖尿病小鼠血糖、控制体重减轻、提高糖耐受量方面有显著性差异,与阳性药物对照组比较无统计学意义.预防作用研究表明各剂量组与空白对照组比较,在预防血糖升高、控制体重减轻方面有显著性差异.结论:山药多糖可显著降低四氧嘧啶糖尿病小鼠的血糖,且预防给药能对抗四氧嘧啶引起的小鼠血糖升高.     

紫外分光光度法测定肾骨颗粒中多糖的含量

摘要目的建立肾骨颗粒中多糖的含量测定方法,为其质量评价提供理论依据。方法采用苯酚 硫酸法显色,紫外分光光度法对肾骨颗粒中多糖的含量进行测定,检测波长为486 nm。结果该方法线性、精密度、准确度、范围、耐用性均良好,高、中、低浓度平均加样回收率分别为97.85%,99.99%,98.35%（n＝9）。 结论该方法灵敏快速,准确可靠,可用于肾骨颗粒中多糖含量的测定。     

毛细管GC法测定南五味子多糖的单糖组成

目的:研究南五味子多糖中单糖的种类和组成比例。方法:以2moL.L-1硫酸溶液水解南五味子多糖,用吡啶溶解干燥的水解产物,硅烷化衍生;采用毛细管气相色谱法测定南五味子多糖的单糖组成:色谱柱为SE-30石英毛细管(30m×0.25mm×0.25μm),进样口温度为220℃,检测器温度为230℃,柱温为195℃。结果:南五味子多糖中含有甘露糖、木糖、半乳糖、果糖、葡萄糖和半乳糖醛酸6种单糖成分,已确定的6种单糖的摩尔比为19.78:2.75:0.149:1:0.381:0.127。结论:该方法简便、灵敏,可以准确测定出南五味子多糖中含有的各种单糖。     

卡介菌多糖核酸对肾病大鼠血清IL-4和IL-12的影响

目的：通过肾病综合征大鼠血清IL-4、IL-12的动态变化,探讨微小病变型肾病综合征（MCNS）的免疫学发病机制,揭示卡介菌多糖核酸（BCG-PNS）防治肾病可能途径。方法：本研究将40只大鼠随机分为正常组、肾病组、治疗组和预防组,每组10只。阿霉素5mg/kg制MCNS模型,BCG-PNS进行防治。观察大鼠一般情况,1、2、4周测24小时尿蛋白,2、4周取血生化仪测定血清白蛋白和总胆固醇水平,ELISA方法检测血清IL-4、IL-12的水平。实验结束时观察大鼠肾脏形态学改变。结果：1与正常组比较,肾病组出现大量的蛋白尿,低白蛋白血症,高胆固醇血症和明显的水肿,血清IL-4升高,IL-12降低,且均呈持续性加重。阿霉素注射4周,治疗组和预防组除IL-12与正常组无显著差异外,其它均有显著性差异。2与肾病组比较,治疗组在阿霉素注射4周,各指标均有显著性改善。预防组在阿霉素注射后2周与同期肾病组比较各指标均存在显著性差异。结论：1MCNS存在TH1/TH2功能紊乱,IL-4、IL-12参与了MCNS的免疫机制。2BCG-PNS可能通过诱导TH1型反应,促进IL-12的分泌,抑制TH2型反应,使IL-4分泌减少,而调整TH1/TH2的平衡,为MCNS防治提供实验依据。     

脑膜炎球菌疫苗研究与疾病防控策略初探

此文介绍了脑膜炎球菌的特点、传播途径、流行趋势及危害性,讨论了防控流行性脑脊髓膜炎暴发的相关策略,并对目前国内外脑膜炎球菌疫苗的研究现状进行了阐述和评价.