Towards improved diagnosis of von Willebrand disease: Comparative evaluations of several automated von Willebrand factor antigen and activity assays

Introduction

von Willebrand disease (VWD) is reportedly the most common bleeding disorder and arises from deficiency and/or defects of von Willebrand factor (VWF). Laboratory diagnosis and typing has important management implications and requires a wide range of tests, including VWF activity and antigen, and involves differential identification of qualitative vs quantitative defects.

Methods

We have assessed several VWF antigen and activity assays (collagen binding [VWF:CB], ristocetin cofactor [VWF:RCo] and the new Siemens INNOVANCE assay [VWF:Ac], employing latex particles and gain of function recombinant glycoprotein Ib to facilitate VWF binding and agglutination without need for ristocetin) using different instrumentation, including the new Sysmex CS-5100, with a large sample test set (n = 600). We included retrospective plus prospective study designs, and also evaluated desmopressin responsiveness plus differential sensitivity to high molecular weight VWF.

Results

VWF:Ag and VWF:RCo results from different methods were respectively largely comparable, although some notable differences were evident, including one high false normal VWF:Ag value (105 U/dL) on a type 3 VWD sample, possibly due to heterophile antibody interference in the latex-based CS-5100 methodology. VWF:Ac was largely comparable to VWF:RCo, but VWF:CB showed discrepant findings to both VWF:RCo and VWF:Ac with some patients, most notably patients with type 2M VWD.

Conclusions

(a) VWF:Ag on different platforms are largely interchangeable, as are VWF:RCo on different platforms, except for occasional (some potentially important) differences, and manufacturer recommended methods may otherwise require some assay optimization; (b) VWF:RCo and VWF:Ac are largely interchangeable, except for occasional differences that may also relate to assay design (differing optimizations); (c) VWF:CB provides an additional activity to supplement VWF:RCo or VWF:Ac activity assays, and is not interchangeable with either.     

A randomized comparison study of Aquacel Ag and Alginate Silver as skin graft donor site dressings

Objective

This study was conducted to compare pain, healing time, infection rate, and cosmetic outcome between Aquacel Ag (convatec) and Alginate Silver (coloplast) as donor site dressings.

Materials and Methods

We conducted a prospective randomized controlled trial of donor site dressings, comparing Aquacel Ag with Alginate Silver. Patients were randomly allocated to donor site dressing with one of these materials. Outcome measures included pain scores at rest and during dressing changes, time to re-epithelialization, cosmetic outcome and infection rate. Results were assessed for significance using the independent t-test (non-parametric data) and the chi-square test (parametric data).

Results

A total of 20 subjects were enrolled in this study. Subjects included in both groups were comparable with no significant differences in demographic data of age, gender, location of burn and type of burns (P > 0.05 evaluated by paired t-test) between both group. The pain scores were found to be higher in Aquacel Ag group than in Alginate Silver group. Time to re-epithelialization was longer in Aquacel Ag group than in Alginate Silver group. There were no significant differences between the two treatment groups with respect to cosmetic outcome and infection rate.

Conclusions

Based on these results, we find that Alginate Silver is better than Aquacel Ag to cover the skin graft donor site.     

ICP-MS法测定喜炎平注射液中重金属及有害元素

目的 建立喜炎平注射液中17种重金属及有害元素的含量测定方法。方法 样品经消解后采用电感耦合等离子体质谱（ICP-MS）法测定,射频功率1 550 W;蠕动泵转速0.3 r/s;等离子气体积流量15 L/min;辅助气体积流量0.2 L/min;载气体积流量1 L/min;采样深度10 mm,重复次数为3次。结果 该方法下Li、Al、V、Cr、Fe、Co、Ni、Cu、As、Ag、Cd、Sn、Sb、Ba、Hg、Pb、Bi的检测限分别为9.584、49.858、0.504、3.016、51.209、0.142、1.116、0.675、0.924、1.421、0.403、2.770、0.711、3.584、0.590、0.411、0.169 ng/mL,定量限分别为28.933、151.085、1.528、9.139、155.179、0.429、3.381、2.046、2.799、4.312、1.220、8.394、2.155、10.861、1.965、1.244、0.513 ng/mL,各元素在一定质量浓度范围内,响应值与质量浓度的线性关系良好（r>0.999 1）,进样精密度RSD在0.8%~3.8%（n=12）,重复性RSD在0.7%~2.0%（n=6）,17种元素的加样回收率在95.7%~104.8%。20批大生产样品检测结果：Ag为未检出,Li和V为检出但低于定量限,Al、Ni、Cu、As、Ba、Hg、Pb最大质量浓度分别为0.685、0.013、0.007、0.006、0.208、0.070、0.027 μg/mL,Cr、Fe、Co、Cd、Sn、Sb、Bi为未检出或检出但低于定量限。结论 方法的专属性、线性、灵敏度、精密度、准确度、耐用性等均良好,可用于喜炎平注射液中Li、Al、V、Cr、Fe、Co、Ni、Cu、As、Ag、Cd、Sn、Sb、Ba、Hg、Pb、Bi 17种元素的含量测定,20批大生产样品中17种元素检测结果均小于限度要求,符合规定。     

健康男性ABO血型与vWF：Ag检测的相关性

用火箭电泳法检测了１２０名正常健康男性（其中Ａ，Ｂ，Ｏ，ＡＢ型各３０人）的血浆ｖＷＦ：Ａｇ（血管性假血友病因子）含量，以判断是否存在有Ａ，Ｂ，Ｏ血型间的差异。结果表明，Ｏ型男性人群的血浆ｖＷＦ：Ａｇ含量低于其他男性血型人群，除ＡＢ与Ｂ型人群外，其他各型人群间血浆ｖＷＦ：Ａｇ含量存在明显差异。     

ICP-MS法测定酒石酸长春瑞滨中有害元素及催化剂银残留

目的：建立电感耦合等离子体质谱法测定酒石酸长春瑞滨中有害元素及催化剂银残留的方法。方法：用微波消解处理样品,电感耦合等离子体质谱内标法测定银、钒、铬、钴、镍、铜、砷、钼、镉、锡、锑、钡、铅、汞的含量。结果：上述14种元素的方法检出限分别为0.003、0.020、0.141、0.069、0.077、0.362、0.031、0.057、0.022、0.078、0.017、0.724、0.095、0.005 ng·mL^-1,线性关系良好（r≥0.9988）,回收率为86%~110%,RSD小于15%;同时,给出了此方法各元素的不确定度评定程序。结论：本方法采用在线加内标,可有效校正仪器漂移,抑制基体干扰,提高准确率,多元素测定便捷、准确、灵敏、可靠,可用于酒石酸长春瑞滨中有害元素及催化剂银残留的测定。     

pET28a-Streptag I-SbpA-Ag85B重组质粒的表达与鉴定

目的 应用分子克隆技术获得纳米级Ag85B蛋白并对其进行鉴定和免疫学特性检测.方法 利用S-layer/Streptag I这一具有自我组装能力的纳米模式嵌合结核杆菌分泌的Ag85B蛋白基因,将其克隆到原核表达载体pET28a（＋）中,并在大肠杆菌中表达Ag85B蛋白,表达后的蛋白经SDS-PAGE和Western blotting鉴定.结果 原核表达重组质粒pET28a-Streptag I-SbpA-Ag85B成功构建,并可在大肠杆菌中诱导表达,得到的Streptag I-Sbpa-Ag85B蛋白经SDS-PAGE和Western blotting鉴定正确,重组蛋白能被结核患者血清识别.结论 重组后的Ag85B蛋白具有较强的免疫反应性.所建立的原核表达体系为新型结核疫苗研制提供了一个新的思路.     

Silver Doped Magnesium Ferrite Nanoparticles: Physico-Chemical Characterization and Antibacterial Activity

Spinel phases, with unique and outstanding physical properties, are attracting a great deal of interest in many fields. In particular, MgFe₂O₄, a partially inverted spinel phase, could find applications in medicine thanks to the remarkable antibacterial properties attributed to the generation of reactive oxygen species. In this paper, undoped and Ag-doped MgFe_2-xAg_xO₄ (x = 0.1 and 0.3) nanoparticles were prepared using microwave-assisted combustion and sol–gel methods. X-ray powder diffraction, with Rietveld structural refinements combined with micro-Raman spectroscopy, allowed to determine sample purity and the inversion degree of the spinel, passing from about 0.4 to 0.7 when Ag was introduced as dopant. The results are discussed in view of the antibacterial activity towards Escherichia coli and Staphylococcus aureus, representative strains of Gram-negative and Gram-positive bacteria. The sol–gel particles were more efficient towards the chosen bacteria, possibly thanks to the nanometric sizes of metallic silver, which were well distributed in the powders and in the spinel phase, with respect to microwave ones, that, however, acquired antibacterial activity after thermal treatment, probably due to the nucleation of hematite, itself displaying well-known antibacterial properties and which could synergistically act with silver and spinel.     

Study of Interaction Mechanism between Positrons and Ag Clusters in Dilute Al–Ag Alloys at Low Temperature

The microstructural evolution of dilute Al–Ag alloys in its early aging stage and at low temperatures ranging from 15 K to 300 K was studied by the combined use of Positron annihilation lifetime spectroscopy (PALS), high resolution transmission electron microscopy (HRTEM), and positron annihilation Coincidence Doppler broadening (CDB) techniques. It is shown that at low temperatures below 200 K, an Ag–vacancy complex is formed in the quenched alloy, and above 200 K, it decomposes into Ag clusters and monovacancies. Experimental and calculation results indicate that Ag clusters in Al–Ag alloys can act as shallow trapping sites, and the positron trapping rate is considerably enhanced by a decreasing measurement temperature.     

Synthesis,characterization and cytotoxic activity of naturally isolated naringin-metal complexes

High-purity naringin was isolated from the fruit peels of Citrus maxima and characterized by various spectroscopic methods like UV and NMR. The isolated compound ligand (HL) was used as ligand-metal complexes synthesis after using Ag (I), Y (III) and Ru (III) metals. These ligand-metal complexes were characterized by elemental analysis, FT-IR, UV–VIS, TGA, molar conductance and magnetic properties. Cytotoxic activity of the isolated naringin and its metal complexes were investigated against two human cancer cell lines namely, white breast Adenocarcinoma (MCF7) and Lung carcinoma (A549) using cell viability assay. Transition metal increased the cytotoxic activity of naringin when they were conjugated. LC50 of Ag ligand complex demonstrated strong cytotoxicity against MCF-7 and A549 cell line that was found higher active more than three and four times the strength, respectively when compared to LC50 of Adriamycin. While LC50 of Adriamycin compound was slightly more active only about 30% and twice the strength of the Ru ligand complex against MCF-7 and A549 cell line, respectively.