Search results for "Reagent"
showing 10 items of 699 documents
Exosomal miRNA analysis in Non-Small Cell Lung Cancer (NSCLC) patients' plasma through qPCR : a feasible liquid biopsy tool
2016
Abstract: The discovery of alterations in the EGFR and ALK genes, amongst others, in NSCLC has driven the development of targeted-drug therapy using selective tyrosine kinase inhibitors (TKIs). To optimize the use of these TKIs, the discovery of new biomarkers for early detection and disease progression is mandatory. These plasma-isolated exosomes can be used as a non-invasive and repeatable way for the detection and followup of these biomarkers. One ml of plasma from 12 NSCLC patients, with different mutations and treatments (and 6 healthy donors as controls), were used as exosome sources. After RNAse treatment, in order to degrade circulating miRNAs, the exosomes were isolated with a comm…
Diastereoselectivity of 5-Methyluridine Osmylation Is Inverted inside an RNA Chain
2016
In this study, we investigated the reaction of the osmium tetroxide-bipyridine complex with pyrimidines in RNA. This reagent, which reacts with the diastereotopic 5-6 double bond, thus leading to the formation of two diastereomers, was used in the past to label thymidine and 5-methylcytosine in DNA. In light of the growing interest in post-transcriptional RNA modifications, we addressed the question of whether this reagent could be used for labeling of the naturally occurring RNA modifications 5-methylcytosine and 5-methyluridine. On nucleoside level, 5-methylcytosine and 5-methyluridine revealed a 5- and 12-fold preference, respectively, over their nonmethylated equivalents. Performing the…
Synthesis, characterization, and cytotoxic activity of copper(II) and platinum(II) complexes of 2-benzoylpyrrole and X-ray structure of bis[2-benzoyl…
2004
Copper(II) and platinum(II) complexes of 2-benzoylpyrrole (2-BZPH) were synthesized and characterized with IR, 1 H and 1 3 C NMR spectroscopies and coordination geometry with ligands arranged in transoid fashion. The crystal structure of [Cu I I (2-BZP) 2 ] was determined by X-ray diffraction. Death of complex treated Jurkat cells was measured by flow cytometry. The bis-chelate complexes [Cu I I (2-BZP) 2 ] and [Pt I I (2-BZP) 2 ] adopt square-planar coordination geometry with ligands, arranged in transoid fashion. Concentrations of 1-10 μM Platinum(II) complexes reduced cell survival from 100% to 20%, in contrast to the copper(II) complex which caused no cell death at a concentration of 10…
ChemInform Abstract: Regio- and Stereoselective Addition of Grignard Reagents to N-Galactosyl-2-pyridone: Synthesis of 4-Substituted 5,6-Didehydro-2-…
2010
Synchronizing the release rates of salicylate and indomethacin from degradable chitosan hydrogel and its optimization by definitive screening design.
2018
Abstract Three types of ionically crosslinked (with citric acid) chitosan discs were loaded with the highly water- soluble drug, sodium salicylate (SS) and the poorly water-soluble drug, indomethacin (Ind). In separate experiments the hydrated discs were immersed in a de-crosslinking solution comprising of different concentrations of calcium chloride, which induced a controlled erosion of the discs, a process which was optimized to synchronize the release rates of the two drugs over a predetermined period of time. The optimization was accomplished by manipulating six factors: chitosan MW, its amount in the formulation, the concentration of the crosslinker agent, the concentration of the de-…
Cytotoxicity of 35 medicinal plants from Sudan towards sensitive and multidrug-resistant cancer cells
2015
Abstract Background Cancer is a complex disease with multiple genetic and epigenetic alterations. Since decades, the hallmark of cancer therapy is chemotherapy. Cytotoxic drugs erase rapidly dividing cells without sufficient differentiation between normal and cancerous cells resulting in severe side effects in normal tissues. Recently, strategies for cancer treatment focused on targeting specific proteins involved in tumor growth and progression. The present study was designed to investigate the cytotoxicity of 65 crude extracts from 35 Sudanese medicinal plants towards various cancer cell lines expressing molecular mechanisms of resistance towards classical chemotherapeutics (two ATP-bindi…
Systematic Study of Several Causes and Effects Due to Absorbent Blanks in Determinations of One Analyte
1999
A systematic study is performed about several factors involved in the measurements when a absorbent blank is used, as molar absorption coefficient of the formed complex, absorbance of the blank at the measured wavelength, and kind of spectrophotometer used (conventional double-beam or diode-array). It is proved that the usual methodology, measuring against reagent blank, produces less accurate measurements than those obtained against solvent blank. On the other hand, use of the H-Point standard additions method provides always equal or better results than the best ones obtained at single wavelengths by using measurements against solvent bank, at the maximum of the formed complex. To test th…
On the Low-Lying Excited States ofsym-Triazine-Based Herbicides
2005
We report a joint computational and luminescence study on the low-lying excited states of sym-triazines, namely, 1,3,5-triazine (1) and the ubiquitous herbicides atrazine [6-chloro-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (2)] and ametryn [6-methylthio-N2-ethyl-N4-isopropyl-1,3,5-triazine-2,4-diamine (3)]. Geometrical structures, energetics, and transition and state properties of I and 2 were computed at the TD-DFT, CASSCF, and CASPT2 levels of theory. The fluorescence and phosphorescence emission spectra, lifetimes, and fluorescence quantum yields were measured for the three compounds, and from these, the energies of the lowest excited states and their corresponding radiative rates…
Determination of Cd, Cu, Pb and Zn content of infant formulas by differential pulse anodic stripping voltammetry (DPASV).
1994
The differential pulse anodic stripping voltammetry (DPASV) method described is based on the one reported by Hasse et al., but adapted to normal laboratory conditions. The values obtained in the estimation of the analytical parameters (linearity, detection and quantification limits, precision and accuracy) show that in the conditions described the method is sensitive enough, reliable and useful for determining these elements in infant formulas. A comparison between DPASV and atomic absorption spectroscopy (AAS) methods in the conditions described here shows that the former is less sensitive but that they are similar in precision. The cadmium, copper, lead and zinc contents of different type…
Fluorimetric determination of amphetamine in urine by flow injection with on-line liquid–liquid extraction
2001
Abstract Determination of amphetamine in urine was performed by batch and flow injection methodologies. The suitable experimental conditions for fluorimetric measurements were established. The liquid–liquid extraction was carried out at pH 13 using diethyl ether as extracting reagent. The measurement conditions were 260 nm and 277 nm for excitation and emission wavelengths, respectively. The method requires standard addition calibration and Youden blank correction. The influence of the main metabolites of amphetamine and metamphetamine were studied. The accuracy and precision of the proposed method was tested and the method is adapted to the flow injection procedure with on-line extraction.