Relaxation effects of clustered particles.

Relations between spatial distribution of superparamagnetic iron oxide (SPIO) particles and the image contrast caused by SPIO were investigated. Actual clustering pattern of particles was measured in the liver and spleen of animals using intravital laser confocal microscopy. SPIO-doped phantoms with and without Sephadex beads were made to simulate these patterns, and relaxation parameters were measured using a 1.5-T clinical scanner. Finally, these results were compared to clinical image data using SPIO particulate agent. Intravital microscopy indicated that the clustering of latex beads was more predominant in hepatic Kupffer cells than in splenic macrophages (P < 0.001). Phantoms without Sephadex beads showed an approximately linear increase of 1/T1 (R1), 1/T2 (R2) and 1/T2* (R2*) values with increasing SPIO concentration. However, with Sephadex beads, R1 and R2 showed little change with increasing SPIO concentration, while R2* showed the same linear increase with SPIO. Also, the R2* values were higher with Sephadex beads. These results were consistent with the clinical imaging data, where signal reduction was significantly smaller in the spleen (-0.4% +/- 27.4%) than in the liver (50.4% +/- 16.8%, P < 0.00001) on T2*-weighted images, but the reduction in the spleen (47.2% +/- 16.1%) was equivalent to the liver (38.8% +/- 26.0%) on T2-weighted images.     

二氢卟吩e6脂质体的制备及影响因素考察

目的:建立二氢卟吩e6脂质体包封率的测定方法,考察各因素对包封率的影响.方法:分别采用Sephadex G50,Sephadex G75凝胶柱分离脂质体和游离药物,优选测定二氢卟吩e6脂质体包封率的方法;以包封率为指标,采用单因素试验考察磷脂质量浓度、胆固醇用量、水化介质、温度及时间对二氢卟吩e6脂质体制备的影响.结果:选择SephadexG50柱色谱法测定二氢卟吩e6的包封率,其对游离药物回收率达100.6％,采用该法测定包封率的重复性RSD＜0.02;磷脂与胆固醇的质量比、药脂比、水化介质对包封率的影响较大.结论:SephadexG50凝胶柱色谱法能方便、快速地测定二氢卟吩e6脂质体的包封率,建立的方法稳定可行.     

凝胶色谱法测定注射用磺苄西林钠的聚合物

目的建立凝胶色谱法测定注射用磺苄西林钠中聚合物的方法。方法采用高效液相色谱法,色谱柱为Sephadex G-10凝胶柱．流动相A为pH7．0的0．05mol·L^-1磷酸盐缓冲液[0．05mol·L^-1磷酸氢二钠溶液-0．05mol·L^-1磷酸二氢钠溶液（61：39）]、流动相B为水．流速为0．5mL·min^-1,检测波长为254nm。结果磺苄西林在50．72-405．76μg·mL^-1与峰面积呈良好的线性关系（r=0．9999）。结论本方法简便、准确、灵敏度高、重现性好。     

Novel method for the depletion of cariogenic bacteria using dextranomer microspheres

Streptococcus mutans is recognized as one of the key contributors to the dysbiotic state that results in dental caries. Existing treatment strategies reduce the incidence of tooth decay, but they also eliminate both the cariogenic and beneficial microbes. Here we introduce a novel treatment alternative using Sephadex, cross‐linked dextranomer microspheres (DMs), typically used for gel filtration chromatography. In addition DM beads can be used for affinity purification of glucosyltransferases (GTFs) from S. mutans. In this study we take advantage of the native pathogenic mechanisms used by S. mutans to adhere, form a biofilm and induce dental caries through the expression of surface‐associated GTFs. We demonstrate that planktonic and biofilm‐grown (adhered to hydroxyapatite‐coated pegs to mimic the tooth surface) S. mutans, specifically and competitively attach to DMs. Further investigation demonstrated that DMs are a specific affinity resin for S. mutans and other cariogenic/pathogenic oral streptococci, whereas other commensal and probiotic strains failed to readily adhere to DMs. Using antimicrobial cargo loaded into the DM lumen, we demonstrate that when in co‐culture with non‐binding to even modestly binding commensal species, S. mutans was selectively killed. This proof of concept study introduces a novel means to safely and effectively reduce the pool of S. mutans and other pathogenic streptococci in the oral cavity with limited disturbance of the necessary commensal (healthy) microbiota when compared with current oral healthcare products.     

龙血竭总黄酮纳米粒的制备工艺研究及其表征

目的：制备龙血竭总黄酮纳米粒（Dragon's blood total flavonoid nanoparticles,DBF-NPs）,并优化其处方和制备工艺。方法：结合HPLC与葡聚糖凝胶柱层析法,构建样品包封率测定方法;以包封率,粒径及外观为综合指标,在单因素试验的基础上进行正交试验设计确定最佳处方及工艺。结果：所优选葡聚糖凝胶柱层析条件为：柱规格10 mm×450 mm,洗脱剂为去离子水,上样量1 mL（含龙血竭总黄酮1 mg）,流速（6±1）mL·h^-1;薄膜超声法为最佳制备方法;最优处方为：有机相与水相体积比1：1,Tween 80浓度为1%,PDLLACOOR 0.7%,龙血竭总黄酮 0.1%;制得纳米粒包封率和平均粒径分别为81%±2.6%、（203±12）nm。结论：通过工艺优化,制得DBF-NPs包封率较高,粒径合适,稳定性良好。     

The binding of human blood platelets to fibrinogen-, fibronectin-, and Arg-Gly-Asp-derivatized Sephadex G-10

The adhesive proteins fibrinogen (FG) and fibronectin (FN) were immobilized to glycine-Sephadex G-10. The derivatized Sephadex G-10 gels were used to bind human blood platelets. For comparison, Gly-Arg-Gly-Asp-Ser-Pro(GRGDSP)-derivatized Gly-Sephadex G-10 was used. FG-, FN-, and GRGDSP-Gly-Sephadex G-10 each bound a substantial number of activated blood platelets (5 X 10⁸ ml^-1 gel) while non-activated platelets were not bound. Binding of ADP-treated blood platelets to the affinity adsorbents was dependent on the ADP-concentration which was used, reaching a near-maximal value at about 10 pM ADP. Platelet binding to the three types of affinity gels could be completely inhibited by dissolved GRGDSP as well as monoclonal anti-platelet glycoprotein IIb/IIIa (GPIIb/IIIa) antibody CLB-C17, which demonstrates that platelet binding specifically involves the fibrinogen binding site on GPIIb/IIIa. Platelet binding to all three affinity gels required free Ca²⁺ and Mg²⁺ ions: platelet binding in the absence of these divalent cations was considerably lower than platelet binding in buffer containing 2 mM Ca²⁺ and 1 mM Mg²⁺. Moreover, activated ethylenediamine-tetraacetate (EDTA)-treated platelets did not bind at all to the affinity gels. The finding that non-activated platelets did not bind to the affinity gels is thought to be related to both the high hydrophilicity of the Sephadex basic material and to the native state of the gel-bound fibrinogen and fibronectin.     

麻醉学小讲课对临床医学本科生教学效果的改进

目的 建立凝胶色谱法测定注射用头孢美唑钠中聚合物。方法 色谱柱为玻璃柱（内径1.3 cm,柱长40 cm）,葡聚糖凝胶G-10（40～120 μm）为填充剂;流动相A为pH 7.0的0.1 mol/L磷酸缓冲液,流动相B为水;体积流量为1.5 mL/min;检测波长为254 nm;蓝色葡聚糖2000溶液的质量浓度为0.1 mg/mL;进样量200 μL。结果 A相中头孢美唑钠进样质量浓度在10～40 mg/L与头孢美唑钠高分子聚合物峰面积呈良好的线性关系（r=0.998 6）。B相中头孢美唑酸进样质量浓度在3.994～79.88 μg/mL线性关系良好（r=0.999 9）。3批样品中高分子聚合物质量分数为0.02%～0.03%。结论 该方法的精密度和准确度均能满足注射用头孢美唑钠中高分子聚合物质量控制的要求。     

凝胶法和超滤法测定rhGH脂质体包封率的比较△

目的:建立两种测定脂质体包封率的方法,并对测定结果进行比较。方法:分别以葡聚糖凝胶法和超滤法分离rhGH脂质体和游离药物,采用HPSEC法测定外水相药物含量,计算包封率,并用SPSS软件进行t检验。结果:两种方法测定不同药脂比的rhGH脂质体包封率,测定结果无显著性差异。结论:凝胶法的建立需详细考察凝胶的种类对分离度的影响;超滤法分离度良好,分离速度快,为优选的方法。     

凌霄花中洋丁香苷的制备

目的 从凌霄花中制备洋丁香苷.方法 凌霄花70％乙醇提取液经D-101型大孔吸附树脂纯化、凝胶Sephadex LH-20柱精制制备洋丁香苷.结果 产品经HPLC、ESI-MS分析确定为洋丁香苷,质量分数＞95％.结论 该方法操作简便,克服耗费大量有机溶剂、收率低等弊端,适合洋丁香苷制各.     

Purification and immunoreactivity of monoclonal antibodies against myeloma-λ chain

Summary In this study, two murine IgM-monoclonal antibodies (IgM-McAbs) against λ chain of myeloma protein from hybridoma ascites were purified by Sephadex G200 chromatography. The eluate of the first peak on absorption at 280 nm formed one precipitation band with rabbit anti-mouse IgM or anti-mouse immunoglobulin in agar gel double diffusion test; it also formed a detectable precipitation line in the IgM reaction area in immunoelectrophoresis. These findings showed that the eluate of the first peak on absorption at 280 nm contained purified IgM-McAbs. It was found in indirect ELISA that the immunoreactivity of the eluate of the first peak was four to five fold higher than that of the original ascites with equimolar protein concentration. Double antibody sandwich ELISA analyses of the immunoreactivity of HRP-conjugated IgM-monoclonal antibodies with λ chain denoted that the purified IgM-McAb-HRP-conjugate might be of practical value in quantitative as well as qualitative assay of λ chains.