Generic simple enzyme immunoassay approach to avert small molecule immobilization problems on solid phases: Application to the determination of tobramycin in serum

Generic simple and sensitive universal enzyme immunoassay approach for the determination of small analytes has been developed to avert the problems associated with small molecule immobilization onto solid phases. The developed assay employed a heterogeneous non-competitive binding format. The assay used anti-analyte antibody coupled to polyacrylamide beads as a solid-phase and β-d-galactosidase enzyme-labeled analyte as a label. In this assay, the analyte in a sample was firstly incubated to react with an excess of the antibody-coupled beads, and then the unoccupied antibody binding sites were allowed to react with the enzyme-labeled analyte. Analyte bound to the antibody-coupled beads was separated by centrifugation, and the enzyme activity of the supernatant was measured spectrophotometrically at 420 nm, after reaction with 4-nitrophenyl-β-d-galactopyranoside as a substrate for the enzyme. The signal was directly proportional to the concentration of analyte in the sample. The optimum conditions for the developed assay were established and applied to the determination of tobramycin, as a representative example of the small analytes, in serum samples. The assay limit of detection was 10 ng mL⁻¹ and the effective working range at relative standard deviation of ≤10% was 40-800 ng mL⁻¹. The assay precisions were acceptable; the relative standard deviations were 4.36-5.17 and 5.62-7.40% for intra- and inter-assay precision, respectively. Analytical recovery of tobramycin spiked in serum ranged from 95.89 ± 4.25 to 103.45 ± 4.60%. The assay results correlated well with those obtained by high-performance liquid chromatography (r = 0.992). The assay described herein has great practical value in determination of small analytes because it is sensitive, rapid, and easy to perform in any laboratory. Although the assay was validated for tobramycin, however, it is also anticipated that the same methodology could be used for essentially any analyte for which a selective antibody exists, and an appropriate enzyme conjugate can be made.     

Modeling Modal Talk in Quantum Mechanics

In this paper, modal and counterfactual logical connectives are defined in an extended framework of branching space-time (Belnap, N. D. (1992). Branching space-time. Synthese 92, 385–434). It is shown that a variety of definitions of the counterfactual can be given. The validity of certain modal statements occurring in quantum mechanics depends on the choice of definition. These considerations can be applied to an analysis of Stapp’s premises LOC1 and LOC2 from his purported proof of non-locality (Stapp, H. P. (1997). Nonlocal character of quantum theory. American Journal of Physics 65, 300–304). It is shown that while the validity of LOC1 depends on the choice of the definition of the counterfactual, LOC2 is absolutely invalid.     

Boundary in context

A contextualist account of modal assertions is sketched that makes their truth sensitive to the presuppositions of the conversation. Support for the account is mustered by considering its application to the context-sensitivity of assertions of subjunctive conditional sentences, explanation sentences, and knowledge sentences.     

SPF规格材弹性模量的频率法测试及其评价

本文首先借助模态试验验证了文中提出的试验装置对试件实现了自由支承, 然后用瞬态激励测试了试件的一阶固有频率,并推算出SPF规格材的弹性模量。根据GB50005-2003《木结构设计规范》,评价了这批SPF规格材的弹性模量达Ⅱc级要求的概率为96.3%。瞬态激励频率法具有快速、简便、重复性好、精度高的优点。该方法对轻型木结构行业的检测工作具有一定的应用价值。     

Changes in MR signal intensity and contrast enhancement of therapeutically irradiated soft tissue

Increased MR signal intensity was observed on T₂-weighted, STIR, and Gadolinium-DTPA-enhanced T₁-weighted images of subcutaneous and muscular soft tissue in 9 of 10 children treated with combination chemotheraphy and radiation therapy (RT) for malignancy in the pelvis or an extremity. Total radiation doses ranged from 59.5 to 65 Gy. Eight of the patients with these changes received hyperfractionated RT (seven for Ewing sarcoma and one for perineal rhabdomyosarcoma); one was treated for pelvic hemangiopericytoma with once-daily fractions. Evidence of soft tissue damage became apparent as early as the sixth week of RT and was seen for up to 69 wk post-RT. There was no clear MR evidence of RT-induced soft tissue damage in one patient, who underwent hyperfractionated RT for pelvic rhabdomyosarcoma. Other MR findings in this group included evidence of bladder wall thickening in three of the seven patients given pelvic RT and increased T₁-weighted signal of irradiated marrow in nine patients. All patients had clinical evidence of skin, soft tissue, or epithelial radiation effects. Increased MR signal intensity secondary to RT-induced damage can be differentiated from widespread tumor by geometric borders that conform to the margins of the radiation field.     

An assay of sulphasalazine,sulphapyridine and its acetylated and hydroxylated metabolites in biological fluids by liquid chromatography

Summary An HPLC assay was developed for the determination of sulphasalazine (salicylazosulphapyridine), and its main metabolites; sulphapyridine, acetylsulphapyridine, hydroxysulphapyridine and acetylhydroxysulphapyridine in human serum, synovial fluid and urine. Sep-Pak C₁₈ cartridge was used for the extraction of the investigated compounds and the added sulphadimidine internal standard. The methylene chloride-chloroform-methanol eluate was evaporated and the dissolved dry residue was injected onto a Hypersil ODS (100×2.1 mm) 5 m microbore, analytical column. A linear gradient was used, the mobile phase was ternary. The assay is sufficiently sensitive for routine therapeutic drug monitoring and phenotyping in patients treated with sulphasalazine.     

超声溶栓

超声溶栓长期为人们所重点研究。本文对超声溶栓技术进行了综述，着重介绍和分析了其发展历史、溶栓机理、技术特点和研究现状，最后对以后的研究工作提出了一些看法。     

Niclosamide & challenges in chemical modifications: A broad review on enhancement of solubility

Niclosamide is classified under World Health Organization's crucial medicines and it is categorized as an anthelmintic drug to target tapeworm infections. In recent findings it is successfully repurposed as a multifunctional drug effective against many diseases. The approach for synthesis of niclosamide is very crisp, simple and affordable. Besides these outstanding activities and easy method of synthesis, the poor solubility which down regulate the bioavailability of niclosamide has prevented its advance development for clinical therapy. This article reviews various methods studied by vast researchers to enhance the solubility which lead to increased efficacy and potential in targeting the diseases. The review also focuses on the application of niclosamide derivatives in different therapeutic uses which proves its broad and vast activity to treat many diseases. The experimental studies to enhance the solubility using chemistry approaches are progressing to achieve the success in developing niclosamide based therapies and broaden its applications.“The experimental study to enhance the solubility by chemistry aspect is progressing continuously to achieve the success in its uses. “Therefore, in present review we have broadly discuss the challenges, synthesis, chemical modification for solubility enhancement and application of niclosamide as gold drug in clinical field”.     

A high-resolution capillary isoelectric focusing method for the determination of therapeutic recombinant monoclonal antibody

Capillary isoelectric focusing (CIEF) is a common choice for separation and analysis of the charge variants and impurities of therapeutic proteins. In this study, we developed a sensitive CIEF analysis method for determining the charge heterogeneity of therapeutic monoclonal antibody (mAb) using Beckman PA800 plus platform. The mixture of 5% Pharmalyte 8-10.5 and 1% Pharmalyte 3-10 was used to overcome the limitation of using single Pharmalyte 3-10 in detecting charge heterogeneity of basic mAb. This approach largely improved the resolution of the heterogeneous peaks. In addition, 3 M urea and 50 mM arginine (Arg) were used to improve the separation as solubilizer and cathodic stabilizer, respectively. Under optimized condition, both acidic and basic peaks of the mAb were separated well. Method qualification results showed good specificity, precision, and linearity within the concentration range of 0.03-0.20 mg/mL for mAb R1. The method was then used for C-terminal lysine (Lys) variants characterization and glycosylation profiles analysis. Furthermore, it also had a wide application in the clone screening process. The highly sensitive and repeatable results highlighted the wide application prospects of this method in biopharmaceutical industry.     

Novel on‐line column extraction apparatus coupled with binary peak focusing for high‐performance liquid chromatography determination of rifampicin in human plasma: A strategy for therapeutic drug monitoring

In order to develop a method that is completely suitable for the routine therapeutic drug monitoring, a sensitive and fully automated on‐line column extraction apparatus in combination with high‐performance liquid chromatography allowing binary peak focusing was developed and validated for the determination of rifampicin in human plasma. Rifapentine was used as an internal standard. The analytical cycle started with the injection of 100 μL of the sample pretreated by protein precipitation in a Venusil SCX extraction column. After the elution, the analytes were transferred and concentrated in an Xtimate C₁₈ trap column. Finally, the trapped analytes were separated by an Xtimate C₁₈ analytical column and were analyzed by an ultraviolet detector at 336 nm. With this new strategy, continuous on‐line analysis of the compounds was successfully performed. The method showed excellent performance for the analysis of rifampicin in plasma samples, including calibration curve linearity (All r were larger than 0.9996), sensitivity (lowest limit of quantification was 0.12 μg/mL), method accuracy (within 6.6% in terms of relative error), and precision (relative standard deviations of intra‐ and interday precision were less than 7.8%). These results demonstrated that the simple, reliable, and automatic method based on on‐line column extraction and binary peak focusing is a promising approach for therapeutic drug monitoring in complex biomatrix samples.