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Analytical Biochemistry

Asuncion Carmona, Stéphane Roudeau, Baptiste L'Homel, Frédéric Pouzoulet, Sarah Bonnet-Boissinot, Yolanda Prezado, Richard Ortega
Metallic nanoparticles have great potential in cancer radiotherapy as theranostic drugs since, they serve simultaneously as contrast agents for medical imaging and as radio-therapy sensitizers. As with other anticancer drugs, intratumoral diffusion is one of the main limiting factors for therapeutic efficiency. To date, a few reports have investigated the intratumoral distribution of metallic nanoparticles. The aim of this study was to determine the quantitative distribution of gadolinium (Gd) nanoparticles after direct intratumoral injection within U87 human glioblastoma tumors grafted in mice, using micro-PIXE (Particle Induced X-ray Emission) imaging...
February 18, 2017: Analytical Biochemistry
Vishal Kamat, Ashique Rafique
Rapid growth in the field of biotherapeutics has led to an increased demand for high-throughput, label-free biosensors exhibiting high sensitivity. To support the current needs, Sierra Sensors introduced a surface plasmon resonance imaging (SPRi) based biosensor, Molecular Affinity Screening System (MASS-1). We assessed the potential utility of MASS-1 to support Regeneron's therapeutic antibody discovery. A large panel of antibody-antigen interactions was characterized using MASS-1 and the kinetic data were compared with the Biacore 4000 biosensor...
February 18, 2017: Analytical Biochemistry
Xin He, Chang Fei Duan, Yong Hua Qi, Jun Dong, Geng Nan Wang, Guo Xian Zhao, Jian Ping Wang, Jing Liu
No abstract text is available yet for this article.
February 18, 2017: Analytical Biochemistry
Raja Chinnappan, Sana Al Attas, Gerrit Koop, Tine van Werven, Wendy E Kaman, Floris J Bikker, Mohammed Zourob
Mastitis in dairy cattle is an inflammatory reaction of the udder tissue. Mastitis increases plasmin levels, leading to an increased proteolysis of milk proteins such as casein, resulting in a significant decrease in milk quality and related dairy products. Due to its key-role in mastitis, we used plasmin proteolytic activity as a biomarker for the detection of mastitis in bovine mastitic milk. Inspired by earlier studies on protease activity using mastitic milk samples, we developed a simple colorimetric assay to distinguish mastitic milk from milk derived from healthy animals...
February 17, 2017: Analytical Biochemistry
Howard Goldfine, Ziqiang Guan
No abstract text is available yet for this article.
February 16, 2017: Analytical Biochemistry
Sébastien Acket, Anthony Degournay, Franck Merlier, Brigitte Thomasset
Metabolic flux analysis is particularly complex in plant cells because of highly compartmented metabolism. Analysis of free sugars is interesting because it provides data to define fluxes around hexose, pentose, and triose phosphate pools in different compartment. In this work, we present a method to analyze the isotopomer distribution of free sugars labeled with carbon 13 using a liquid chromatography-high resolution mass spectrometry, without derivatized procedure, adapted for Metabolic flux analysis. Our results showed a good sensitivity, reproducibility and better accuracy to determine isotopic enrichments of free sugars compared to our previous methods [5, 6]...
February 14, 2017: Analytical Biochemistry
Parviz Moradi, Brian Ford-Lloyd, Jeremy Pritchard
Thyme as a perennial herb has been recognized globally for its antimicrobial, antiseptic and spasmolytic effects. In this investigation, we have used non-targeted metabolite and volatile profiling combined with the morpho-physiological parameters in order to understand the responses at the metabolite and physiological level in drought sensitive and tolerant thyme plant populations. The results at the metabolic level identified the significantly affected metabolites. Significant metabolites belonging to different chemical classes consisting amino acids, carbohydrates, organic acids and lipids have been compared in tolerant and sensitive plants...
February 13, 2017: Analytical Biochemistry
J Rose Stoller, Kurt Wagschal, Charles C Lee, Douglas B Jordan
We recently reported on the kinetics of the polygalacturonase TtGH28 acting on trimer and dimer substrates. When the starting substrate for hydrolysis is the trimer, the product dimer is also subject to hydrolysis, resulting in discrepancies when either the concentration of dimer or monomer product is used for analysis of trimer hydrolysis. Here, we derive a method for determining catalytic rates of exo-hydrolases acting on trimer (and higher order) substrates when products may also be substrates for hydrolysis and show how this correction may be applied for TtGH28...
February 12, 2017: Analytical Biochemistry
Nassim Tayari, Arend Heerschap, Tom W J Scheenen, Thiele Kobus
Proton magnetic resonance spectroscopic imaging ((1)H MRSI) enables non-invasive assessment of certain metabolites in the prostate gland. Several studies have demonstrated that this metabolic information, in combination with anatomical information from T2-weighted MR imaging significantly improves prostate cancer detection, localization and disease characterization. The technology of (1)H MRSI is continuously evolving with improvements of hardware and acquisition methods. Recently, (31)P and (13)C MRSI of the prostate have regained new interest after a dormant period of decades...
February 3, 2017: Analytical Biochemistry
Voin Petrovic, Camilla Olaisen, Animesh Sharma, Anala Nepal, Steffen Bugge, Eirik Sundby, Bård Helge Hoff, Geir Slupphaug, Marit Otterlei
The Multiplexed Inhibitor Bead (MIB) assay is a previously published quantitative proteomic MS-based approach to study cellular kinomes. A rather extensive procedure, need for multiple custom-made kinase inhibitors and an inability to re-use the MIB-columns, has limited its applicability. Here we present a modified MIB assay in which elution of bound proteins is facilitated by on-column trypsinization. We tested the modified MIB assay by analyzing extract from three human cancer cell lines treated with the cytotoxic drugs cisplatin or docetaxel...
February 3, 2017: Analytical Biochemistry
Jyotsana Mehta, Neha Bhardwaj, Sanjeev K Bhardwaj, Satish K Tuteja, Priya Vinayak, A K Paul, Ki-Hyun Kim, Akash Deep
The widespread use of pesticides has immense effect on increased crop productions. However, they are also responsible for posing detrimental health hazards and/or for contaminating the environment with chemical residues. A routine and an on-field detection of pesticide residues in different food, water, and soil samples has become a need of the hour for which biosensors can offer a viable alternative. The present work reports a functionalized graphene quantum dot (GQD) based screen printed electrochemical immunosensor for the detection of parathion...
February 2, 2017: Analytical Biochemistry
Faeze Khakbaz, Mohamad Mahani
Carbon quantum dots have been proposed as an effective platform for miRNA detection. Carbon dots were synthesized by citric acid. The synthesized dots were characterized by dynamic light scattering, UV-Vis spectrophotometry, spectrofluorimetry, transmission electron microscopy and FT-IR spectrophotometry. The fluorescence quantum yield of the synthesized dots was determined using quinine sulfate as the standard. The FAM-labeled single stranded DNA, as sensing element, was adsorbed on dots by π-π interaction...
January 31, 2017: Analytical Biochemistry
Joana Smirnovienė, Vytautas Smirnovas, Daumantas Matulis
The Ki of carbonic anhydrase (CA) inhibitors is often determined by the stopped- flow CO2 hydration assay, the method that directly follows the inhibition of CA enzymatic activity. However, the assay has limitations, such as largely unknown concentration of CO2 and the inability to determine the Ki below several nM. The widely used direct binding assay, isothermal titration calorimetry, also does not determine the Kd below several nM. In contrast, the thermal shift assay can accurately determine picomolar affinities...
January 31, 2017: Analytical Biochemistry
Jing-Jing Chen, Guo-Qing Li, Amit Pratush, Sharmin Jahan, Fan-Zhi Kong, Hua Xiao, Liu-Yin Fan, Cheng-Xi Cao
A ring-shaped electroeluter (RSE) was designed for protein recovery from polyacrylamide gel matrix. The RSE was designed in such a way that a ring-shaped well was used to place gel slices and an enrichment well was used to collect eluted protein samples. With HSA as model protein, the electroelution time was less than 30 min with 80% recovery rate, and the concentration of recovered protein was 50 times higher than that of conventional method. The RSE could be reused at least ten times. The developed device makes great advance towards economic electroelution of biomolecules (such as proteins) from gel matrix...
January 27, 2017: Analytical Biochemistry
Xuan Ni, Bing Xia, Lumei Wang, Jing Ye, Gaoshang Du, Haiwei Feng, Xiaotong Zhou, Tong Zhang, Wenhao Wang
In this paper, we developed a fluorescent aptasensor for 17β-estradiol (E2) determination in aqueous solution using label-free E2-specific aptamer, gold nanoparticles (AuNPs) and Rhodamine B (RhoB) as sensing probe, fluorescent quencher and fluorescent indicator respectively. In the absence of E2, AuNPs were wrapped by E2 aptamer and maintained dispersed in NaCl solution basically. These dispersed AuNPs could effectively impair the originally high fluorescence of RhoB. Contrarily, in the presence of E2, E2 aptamer could specifically combine with E2 to form E2-aptamer complex, so the AuNPs were released by E2 aptamer and aggregated under the influence of NaCl...
January 27, 2017: Analytical Biochemistry
Gianluca Catucci, Isabelle Polignano, Debora Cusumano, Claudio Medana, Gianfranco Gilardi, Sheila J Sadeghi
Human hepatic flavin-containing monooxygenase 3 is a phase I drug-metabolizing enzyme that is responsible for the oxidation of a variety of drugs and xenobiotics. This work reports on a high throughput rapid colorimetric assay for the screening of substrates or inhibitors of this enzyme. The method is based on the competition of two substrates for access to the active site of hFMO3 whereby the enzymatic product of the first drug converts nitro-5-thiobenzoate (TNB, yellow) to 5,5'-dithiobis (2-nitrobenzoate) (DTNB, colourless)...
January 27, 2017: Analytical Biochemistry
Buenafe T Arachea, Michael C Wiener
The Intramolecular Quenched Fluorescence (IQF) protease assay utilizes peptide substrates containing donor-quencher pairs that flank the scissile bond. Following protease cleavage, the dequenched donor emission of the product is subsequently measured. Inspection of the IQF literature indicates that rigorous treatment of systematic errors in observed fluorescence arising from inner-filter absorbance (IF) and non-specific intermolecular quenching (NSQ) is incompletely performed. As substrate and product concentrations vary during the time-course of enzyme activity, iterative solution of the kinetic rate equations is, generally, required to obtain the proper time-dependent correction to the initial velocity fluorescence data...
January 22, 2017: Analytical Biochemistry
Marta Lai, Rolf Gruetter, Bernard Lanz
The combination of dynamic (13)C MRS data under infusion of (13)C-labeled substrates and compartmental models of cerebral metabolism enabled in vivo measurement of metabolic fluxes with a quantitative and distinct determination of cellular-specific activities. The non-invasive nature and the chemical specificity of the (13)C dynamic data obtained in those tracer experiments makes it an attractive approach offering unique insights into cerebral metabolism. Genetically engineered mice present a wealth of disease models particularly interesting for the neuroscience community...
January 21, 2017: Analytical Biochemistry
Ladislav Valkovič, Marek Chmelík, Martin Krššák
In addition to direct assessment of high energy phosphorus containing metabolite content within tissues, phosphorus magnetic resonance spectroscopy ((31)P-MRS) provides options to measure phospholipid metabolites and cellular pH, as well as the kinetics of chemical reactions of energy metabolism in vivo. Even though the great potential of (31)P-MR was recognized over 30 years ago, modern MR systems, as well as new, dedicated hardware and measurement techniques provide further opportunities for research of human biochemistry...
January 21, 2017: Analytical Biochemistry
Nuno Pedrosa de Barros, Johannes Slotboom
The quality of MR-Spectroscopy data can easily be affected in in vivo applications. Several factors may produce signal artefacts, and often these are not easily detected, not even by experienced spectroscopists. Reliable and reproducible in vivo MRS-data requires the definition of quality requirements and goals, implementation of measures to guarantee quality standards, regular control of data quality, and a continuous search for quality improvement. The first part of this review includes a general introduction to different aspects of quality management in MRS...
January 21, 2017: Analytical Biochemistry
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