Growth and electrochemical activity of the poly-l-lysine|poly-l-glutamic acid thin layer films: an EQCM and electrochemical study

Quartz crystal microbalance (QCM) measurement and cyclic voltammetry were used to study the layer-by-layer growth of poly-l-lysine (p-Lys) and poly-l-glutamic acid (p-Glu) thin films and their ability to act as support for redox relays between metal electrodes and redox species in organic electrolytes. The mass of the film grown from buffered solution at constant pH depends on the composition of the buffer used. The growth proceeds in several stages with different mass increments for each poly-l-lysine and poly-l-glutamic acid layer. Ferro/ferricyanide confined into the polypeptide films can play the role of a redox relay between the electrode surface and the organic electrolyte. This was demonstrated on the impregnated polypeptide film|1,2-dichloroethane interface with decamethylferrocene dissolved as redox species in the organic phase. The transport of the ferro/ferricyanide in the polypeptide film is the rate limiting step of the electron transfer process. The diffusion coefficient of the ferro/ferricyanide determined from voltammetric experiments was of the order of 10^?11–10^?12 cm² s^?1. The bimolecular rate constant of the electron transfer reaction was found to be 0.2 cm s^?1 M^?1.     

多肽生长因子对牙周膜细胞的影响

目的对多肽生长因子对牙周膜细胞(periodontal ligament cell,PDLC)影响的研究进行综述。方法广泛查阅近年国内外多肽生长因子对牙周膜细胞影响的相关文献,并进行回顾与综合分析。结果PDLC的增殖和多向分化是牙周组织再生的基础。多肽生长因子对PDLC功能影响的研究成为牙周组织再生研究的热点之一。多肽生长因子在PDLC的移行、生长、增殖、分化、蛋白质和基质合成上均起着重要作用。结论多肽生长因子可应用于牙周组织的再生治疗,但还需进一步深入研究。     

Primary structure similarities in canine cardiac cathepsin D polypeptide chains

Canine cardiac cathepsin D was purified approximately 1000-fold to homogeneity by sequential acid precipitation, affinity chromatography and gel filtration. The purified enzyme was homogeneous on sodium dodecyl sulphate (SDS) polyacrylamide gel electrophoresis and consisted of two polypeptide chains of mol. wt 29 000 ± 2500; n = 6 (designated the A chain) and 13 000 ± 1000, n = 6 (designated the B chain). Separation of the A and B polypeptide chains using gel filtration in the presence of guanidine hydrochloride (6 mol/l) followed by amino acid analysis revealed the presence of a similar amino acid composition in each polypeptide. N-terminal analysis showed that glycine was the sole N-terminal amino acid residue in each chain, while tryptic digestion and subsequent peptide mapping gave 17 major peptides and 6 major peptides for the A and B chains respectively. Three peptide fragments were found to be common to both polypeptide chains.Extracts of canine cardiac tissue did not contain free A or B chains of cathepsin D, however a high molecular weight form of the enzyme (mol. wt 130 000) was observed with a specific activity (U/μg immunoreactive cathepsin D) similar to that of the active undissociated (mol. wt 42 000) enzyme.Immunodiffusion studies using antibodies raised against the whole enzyme showed a reaction of complete identity between the A and B polypeptide chains and undissociated enzyme. Use of the A and B chains in a radioimmunoassay developed for measurement of the undissociated cathepsin D revealed that the A chain bound antibody raised against the undissociated enzyme equally as well as the undissociated enzyme, while the B chain was approximately 100 times less effective at binding the antibody.The results suggest that there may be some degree of similarity in primary structure between the A and B polypeptide chains of canine cardiac cathepsin D. This similarity in primary structure may represent the suggested areas of sequence homology surrounding the active site aspartate residues known to be characteristic of this particular class of acid proteases.     

丙泊酚对体外循环期间血浆内皮素及心钠素的影响

目的了解不同剂量丙泊酚对体外循环期间血浆内皮素及心钠素的影响。方法20例风湿性心脏瓣膜病患者,随机分为两组,体外循环期间以全凭丙泊酚(>6 mgkg.h-1)控制血压组(P)和丙泊酚(4 mg/kg.h-1)加尼卡地平控制血压组(N),各10例,两组体外循环前后麻醉用药相同;监测指标:分别于入室建立有创动脉压监测后(T1)、体外循环前(T2)、体外循环30min(T3)、停体外循环10min(T4)记录各时点的平均动脉压(MAP),同时采集动脉血2ml,检测各时点血浆内皮素(ET)、心钠素(ANP)。结果两组各时点血流动力学指标无统计学意义;两组间各时间点的ET、ANP浓度组间比较无统计学意义;组内比较:ET水平在T3、T4时显著升高,与T1、T2相比有统计学意义;ANP浓度各时间点相比均无统计学意义。结论体外循环期间单纯应用丙泊酚与小剂量丙泊酚加尼卡地平均可维持血压平稳,对应急激素内皮素及心钠素的影响无明显差异。     

温胃汤联合奥美拉唑、阿莫西林、克拉霉素治疗Hp阳性胃溃疡的疗效

目的研究温胃汤联合奥美拉唑、阿莫西林、克拉霉素治疗Hp阳性胃溃疡的疗效。方法选择2013年6月~2016年12月期间在淄博矿业集团有限责任公司中心医院诊断为Hp阳性胃溃疡的98例患者作为研究对象,采用随机数表法将入组患者分为两组,对照组接受常规西医药物治疗,联合组接受温胃汤联合常规西医药物治疗。治疗后8周时,评估临床疗效、检测Hp转阴情况及血清中炎性因子、多肽类激素的含量。结果治疗后8周时,联合组患者的整体疗效显著优于对照组,Hp根除率为83.67%、显著高于对照组的67.34%;联合组患者血清中C反应蛋白(CRP)、白细胞介素-1(IL-1)、IL-6、肿瘤坏死因子-α(TNF-α)、胃动素(MTL)、肾上腺髓质素(AM)、胃泌素(Gas)的含量均显著低于对照组。结论温胃汤联合西药治疗Hp阳性胃溃疡能够改进疗效、提高Hp根除率、抑制炎症反应并调节多肽类激素的分泌。     

Neutralizing antibody and protective immunity to SARS coronavirus infection of mice induced by a soluble recombinant polypeptide containing an N-terminal segment of the spike glycoprotein

A secreted, glycosylated polypeptide containing amino acids 14 to 762 of the SARS coronavirus (SARS-CoV) spike protein and a polyhistidine tag was expressed in recombinant baculovirus-infected insect cells. Mice received the affinity-purified protein with either a saponin (QS21) or a Ribi (MPL + TDM) adjuvant subcutaneously and were challenged intranasally with SARS-CoV. Both regimens induced binding and neutralizing antibodies and protection against SARS-CoV intranasal infection. However, the best results were obtained with QS21 and protein, which provided the highest antibody as well as complete protection of the upper and lower respiratory tract.     

In vitro translation of mRNA from Toxocara canis larvae

300 micrograms of total RNA was extracted from 1 ml of packed Toxocara canis larvae by centrifugation through a 5.7 M cesium chloride cushion. 60 micrograms of polyadenylated messenger RNA was separated from 300 micrograms of total RNA in an oligothymidylic acid-cellulose gel column. The in vitro translation of the mRNA, isolated from T. canis larvae, was carried out using the rabbit reticulocyte cell-free translation system. Incorporation of [35S]methionine into trichloroacetic acid precipitable material in the lysate containing mRNA was 4-5 times greater than that of control. Translation products were analysed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) followed by autoradiography. Many polypeptides ranging in molecular weight from 10000 to 100000 were synthesised in the lysate. A T. canis positive human serum was mixed with translation products to form antigen-antibody complexes, which were then absorbed by Staphylococcus aureus Cowan 1 strain and analysed by the autoradiography of SDS-PAGE. Three antigenic polypeptides with molecular weights of 49000, 27000 and 22000 which reacted specifically with IgG antibody in T. canis positive human serum, were demonstrated. The 27000 MW polypeptide reacted particularly strongly with the IgG antibody.     

Turning the clock forward: New pharmacological and non pharmacological targets for the treatment of obesity

AimsObesity and its main metabolic complication, type 2 diabetes, have attained the status of a global pandemic; there is need for novel strategies aimed at treating obesity and preventing the development of diabetes. A healthy diet and exercise are basic for treatment of obesity but often not enough. Pharmacotherapy can be helpful in maintaining compliance, ameliorating obesity-related health risks, and improving quality of life. In the last two decades, the knowledge of central and peripheral mechanisms underlying homeostatic and hedonic aspects of food intake has significantly increased. Dysregulation of one or more of these components could lead to obesity.Data synthesisIn order to better understand how potential innovative treatment options can affect obesity, homeostatic and reward mechanisms that regulate energy balance has been firstly illustrated. Then, an overview of potential therapeutic targets for obesity, distinguished according to the level of regulation of feeding behavior, has been provided.Moreover, several non-drug therapies have been recently tested in obesity, such as non-invasive neurostimulation: Transcranial Magnetic Stimulation or Transcranial Direct Current Stimulation. All of them are promising for obesity treatment and are almost devoid of side effects, constituting a potential resource for the prevention of metabolic diseases.ConclusionsThe plethora of current anti-obesity therapies creates the unique challenge for physicians to customize the intervention, according to the specific obesity characteristics and the intervention side effect profiles; moreover, it allows multimodal approaches addressed to treat obesity and metabolic adaptation with complementary mechanisms.     

精甘天三肽对肾小球系膜细胞FAK及HA表达的影响

目的 观察精-甘-天(RGD)三肽对肾小球系膜细胞(GMC)增殖、粘着斑激酶(FAK)和透明质酸(HA)表达的影响。方法 采用RGD体外诱导培养大鼠GMC,采用MTT法测定细胞增殖、免疫组织化学方法测定FAK表达、放射免疫法测定HA含量。结果 RGD处理后,细胞由梭形变为圆形或卵圆形,并出现脱壁、悬浮。与正常对照组相比,RGD能降低系膜细胞的增殖;RGD 1mmol／L作用24h分别导致FAK表达平均灰度值降低3．10％,HA含量下降5．64％;4mmol／L作用8h及24h分别导致FAK表达平均灰度值降低6．50％和15．95％,HA含量下降6．37％和18．43％。RSD对细胞增殖、FAK及HA表达无影响。结论 RGD肽可使细胞粘附降低,导致增殖力下降,ECM成分分泌减少。     

市售不同来源福林试剂对多肽含量测定结果的影响

摘 要 目的：研究市售不同来源福林试剂对肌氨肽苷注射液中多肽含量测定结果的影响。方法: 采用福林酚法测定多肽的含量;以牛血清白蛋白为对照制备标准溶液并绘制标准曲线;使用不同来源的福林试剂进行测定;应用统计学方法分析研究不同来源福林试剂对测定结果的影响。结果: 多肽含量在0.024 9～0.224 1 mg·mL^-1浓度范围内线性关系良好,平均回收率为96.4%（RSD=1.5%,n=9）; 统计分析结果表明,使用不同来源福林试剂测得的结果有显著性差异。结论:市售不同品牌福林试剂对肌氨肽苷注射液中多肽含量测定的结果具有显著性影响,使用前应对福林试剂进行质量确认。