Search results for "Reagent"
showing 10 items of 699 documents
Photoinduced functionalization of diterpenes: transformation of the C-20 methyl of atractyligenin into a carbomethoxymethyl or carbamoylmethyl group
2003
Abstract Irradiation of the nor-diterpene atractyligenin 1a and of its methyl ester 1b at λ=254 nm in methanol or in methanol in the presence of nitrogen nucleophiles such as ammonia or methylamine gave, besides the decarboxylation product 2, the ester 3a or the amides 3b, 3c, respectively, providing the transformation of the C-20 angular methyl into a carbomethoxymethyl or carbamoylmethyl group. A photochemical pathway involves formation of C-19/C-20 bond in the excited state, followed by a collapse into a ketene intermediate which will capture the nucleophilic reagent.
Detection of Norovirus Antigens from Recombinant Virus-Like Particles and Stool Samples by a Commercial Norovirus Enzyme-Linked Immunosorbent Assay K…
2006
ABSTRACT The commercial norovirus enzyme-linked immunosorbent assay kit was evaluated for its reactivity to recombinant virus-like particles and the detection of natural viruses from stool samples of Japanese infants and children with sporadic acute gastroenteritis compared to reverse transcription-PCR. The kit had a sensitivity of 76.3% and a specificity of 94.9%. Our results clearly indicated that the kit allows the detection of the most prevalent genotype, GII/4. In order to increase the sensitivity of the kit, the reactivity with norovirus of GII/3 and GII/6 genotypes needs to be improved.
Comparison of the BD Directigen Flu A+B Kit and the Abbott TestPack RSV with a multiplex RT-PCR ELISA for rapid detection of influenza viruses and re…
2005
ABSTRACTThe Directigen Flu A+B enzyme immunoassay and the Abbott TestPack RSV enzyme immunoassay were each compared with a multiplex RT-PCR ELISA by testing 635 nasopharyngeal aspirates collected from children aged < 16 years who had been hospitalised with acute respiratory tract infection during the epidemic season 2002–2003. In this study, the sensitivity of the Directigen Flu A+B assay was unacceptably low (29.3% and 10.0%, respectively) for the detection of influenza A and B viruses. The sensitivity of the Abbott TestPack RSV assay (77.4%) was acceptable and in agreement with the multiplex RT-PCR ELISA.
Performance of the COBAS AMPLICOR HCV MONITOR Test, Version 2.0, an Automated Reverse Transcription-PCR Quantitative System for Hepatitis C Virus Loa…
2000
ABSTRACT A clinical evaluation of an automated quantitative PCR assay, the COBAS AMPLICOR HCV MONITOR test, version 2.0 (v2.0), was carried out to assess the performance of this test in comparison with that of the previous, manual version, the AMPLICOR HCV MONITOR test, and with that of nested PCR. Serial dilutions of serum samples infected with genotype 1b, 2a, or 3, as well as synthetic RNA transcripts and serum samples derived from 87 patients with chronic hepatitis C and infected with genotype 1a, 1b, 2a, 2b, 3a, 3b, 4, or 5, were analyzed to determine the ability of the system to efficiently quantify various hepatitis C virus (HCV) genotypes. These experiments showed that the COBAS AMP…
Evaluation of the diagnostic performances of two commercially available assays for the detection of enteric adenovirus antigens
2021
The performance of 2 antigenic commercial assays for enteric adenovirus (AdV) infection, bioNexia Rota-Adeno ImmunoChromatographic Tests (ICT) and LIAISON® Adenovirus ChemiLuminescence Immuno Assays (CLIA), was evaluated on 321 stools from children hospitalized for acute gastroenteritis in Palermo, Italy, using a Real time-PCR (Rt-PCR) as reference method. The CLIA showed higher sensitivity (77% vs 60%), accuracy (94.4 vs 90.9) and concordance (k: 0.81 vs 0.67) with respect to ICT, despite equivalent specificity (98.8%). Using the Ct values of the Rt-PCR as a proxy of the fecal viral load, similar Ct values (mean 9.32 vs 9.89) were observed among the true positive samples, whilst a signific…
A novel bio-orthogonal cross-linker for improved protein/protein interaction analysis
2015
International audience; The variety of protein cross-linkers developed in recent years illustrates the current requirement for efficient reagents optimized for mass spectrometry (MS) analysis. To date, the most widely used strategy relies on commercial cross-linkers that bear an isotopically labeled tag and N-hydroxysuccinimid-ester (NHS-ester) moieties. Moreover, an enrichment step using liquid chromatography is usually performed after enzymatic digestion of the cross-linked proteins. Unfortunately, this approach suffers from several limitations. First, it requires large amounts of proteins. Second, NHS-ester cross-linkers are poorly efficient because of their fast hydrolysis in water. Fin…
2,8-Diazido-ATP — a short-length bifunctional photoaffinity label for photoaffinity cross-linking of a stable F1 in ATP synthase (from thermophilic b…
1995
Abstract To demonstrate the direct interfacial position of nucleotide binding sites between subunits of proteins we have synthesized the bifunctional photoaffinity label 2,8-diazidoadenosine 5′-triphosphate (2,8-DiN3ATP). UV irradiation of the F1-ATPase (TF1) from the thermophilic bacterium PS3 in the presence of 2,8-DiN3ATP results in a nucleotide-dependent inactivation of the enzyme and in a nucleotide-dependent formation of α-β crosslinks. The results confirm an interfacial localization of all the nucleotide binding sites on TF1.
Synthesis, Crystal Structure, Magnetic Properties, and Theoretical Studies of [{Cu(mepirizole)Br}2(μ-OH)(μ-pz)] (Mepirizole = 4-Methoxy-2-(5-methoxy-…
2003
A novel mu-pyrazolato-mu-hydroxo-dibridged copper(II) complex has been synthesized and structurally characterized: [(Cu(mepirizole)Br)2(mu-OH)(mu-pz)] (mepirizole=4-methoxy-2-(5-methoxy-3-methyl-1H-pyrazol-1-yl)-6-methylpyrimidine; pz=pyrazolate). The title compound crystallizes in the monoclinic system, space group P2(1)/c, with a=15.618(2) A, b=15.369(3) A, c=16.071(3) A, and beta=112.250(1) degrees. The structure is built up of dinuclear [(Cu(mepirizole)Br)2(mu-OH)(mu-pz)] units with five-coordinated copper(II) ions (CuBrN3O chromophores) linked by mu2-OH and mu2-pyrazolato bridges that are well separated from each others. The intramolecular copper-copper distance is 3.378(3) A. Magnetic…
Aminobisphenolate supported tungsten disulphido and dithiolene complexes
2015
Dioxotungsten(vi) complexes with tetradentate amino bisphenolates were converted into the corresponding Cs-symmetric amino bisphenolate disulphido complexes by a reaction with either Lawesson's reagent or P2S5. Further reaction with diethyl acetylenedicarboxylate leads to the formation of diamagnetic tungsten(iv) dithiolene compounds. The syntheses, crystal structures, spectroscopic and electrochemical characterization of such disulphido and dithiolene complexes are presented.
Combining reactive triblock copolymers with functional cross-linkers: A versatile pathway to disulfide stabilized-polyplex libraries and their applic…
2017
Therapeutic nucleic acids such as pDNA hold great promise for the treatment of multiple diseases. These therapeutic interventions are, however, compromised by the lack of efficient and safe non-viral delivery systems, which guarantee stability during blood circulation together with high transfection efficiency. To provide these desired properties within one system, we propose the use of reactive triblock copolypept(o)ides, which include a stealth-like block for efficient shielding, a hydrophobic block based on reactive disulfides for cross-linking and a cationic block for complexation of pDNA. After the complexation step, bifunctional cross-linkers can be employed to bio-reversibly stabiliz…