Search results for "kinetics"

Cross-Reactivity of Epstein-Barr Virus-Specific Immunoglobulin M Antibodies with Cytomegalovirus Antigens Containing Glycine Homopolymers

2001

ABSTRACTTimely and reliable detection of acute primary human cytomegalovirus (HCMV) infection is important in prenatal screening programs and for differential diagnosis of infectious mononucleosis-like disease. Enzyme-linked immunosorbent assays (ELISAs) based on HCMV proteins enable the sensitive detection of immunoglobulin M (IgM) antibodies during primary infection. However, concerns have been raised about possible cross-reactivities of the HCMV antigens used for the design of such ELISAs with IgM antibodies induced by Epstein-Barr Virus (EBV). In this study we investigated whether IgM antibodies generated during acute EBV infection reacted with recombinant HCMV antigens. Serum samples f…

Real-time reverse transcription PCR analysis of expression of atrazine catabolism genes in two bacterial strains isolated from soil

2004

Abstract The level of expression of highly conserved, plasmid-borne, and widely dispersed atrazine catabolic genes ( atz ) was studied by RT-qPCR in two telluric atrazine-degrading microbes. RT-qPCR assays, based on the use of real-time PCR, were developed in order to quantify atzABCDEF mRNAs in Pseudomonas sp. ADP and atzABC mRNAs in Chelatobacter heintzii . atz gene expression was expressed as mRNA copy number per 10 6 16S rRNA. In Pseudomonas sp. ADP, atz genes were basally expressed. It confirmed atrazine-degrading kinetics indicating that catabolic activity starts immediately after adding the herbicide. atz gene expression increased transitorily in response to atrazine treatment. This …

Flow cytometric assay for quantifying opsonophagocytosis and killing of Staphylococcus aureus by peripheral blood leukocytes.

1992

We describe a novel flow cytometric method for quantifying opsonophagocytosis and killing of Staphylococcus aureus in cell-rich plasma obtained after dextran sedimentation of erythrocytes. To analyze opsonophagocytosis, phagocytes were labeled with a phycoerythrin-conjugated monoclonal antibody and were incubated with viable staphylococci containing carboxyfluorescein as a vital fluorescent dye. Phagocytosing cells assumed a dual, orange-green fluorescence. The relative numbers of bacteria associating with phagocytes could be determined by quantifying the decrease of free green fluorescent particles. A parallel incubation of fluorescent bacteria with unlabeled cell-rich plasma was performed…

Stability of chitin synthetase in cell-free preparations of a wild-type strain and a 'slime' variant of Neurospora crassa.

1991

Chitin synthetase activity in cell-free preparations from a wild-type strain and a 'slime' variant of Neurospora crassa was monitored over many days in samples stored at 0 degrees C. Total activity in whole-cell-free extracts and low-speed supernatants from both organisms was very unstable, losing more than 90% of the initial activity on storage at 0 degrees C for 96 h. Chitin synthetase detection was not masked by chitinase activity present in the preparations. Gel-filtration chromatography of these preparations increased the stability of the activity from the 'slime' variant, whereas removal of particulate structures by high-speed centrifugation stabilized the chitin synthetase activity i…

Kinetic study of ionic liquid synthesis in a microchannel reactor

2010

Abstract A microchannel reaction system, mainly consisting of a micromixer and a tubular reactor, was used to investigate the kinetics of butylation of 1-methyl-imidazole [MIM] for the synthesis of the ionic liquid 1-butyl-3-methylimidazolium bromide ([BMIM]Br). The low variance (σθ2 = 0.019) of the residence time distribution, measured by a step stimuli–response tracer method, implies that this reaction system could be regarded as a plug flow reactor. As a fast and reliable method, the titration of bromide was established to determine the yield of [BMIM]Br. The reaction kinetics was studied by varying the molar ratio of 1-bromobutane [BrBu] to [MIM] (1.04–1.49) and temperature (75–90 °C). …

KA-672 inhibits rat brain acetylcholinesterase in vitro but not in vivo.

1999

Abstract KA-672, a lipophilic benzopyranone derivative which is currently under development as a cognitive enhancer and antidementia drug, has previously been shown to have facilitatory effects on learning and memory in rats at doses of 0.1–1 mg/kg. We now report that KA-672 inhibited the activity of acetylcholinesterase (AChE), measured in vitro in rat brain cortical homogenate, with an IC 50 value of 0.36 μ M indicating that KA-672 may improve cognitive functions as a consequence of AChE inhibition. However, when we employed the microdialysis procedure to monitor acetylcholine (ACh) release from rat hippocampus, no effect of KA-672 (0.1–10 mg/kg) was found, indicating a lack of inhibition…

Quantitative In Vivo Microdialysis in Pharmacokinetic Studies

2012

Influence of aeration on the localized trenching on aluminium alloys

2010

This paper aims to make the difference between alcalinisation and micro-galvanic corrosion in the mechanism of the corrosion of Al alloys. Using a pH microprobe, the pH changes inside a pure water droplet deposited on a thermal aged 2011 aluminium alloy were scanned. These pH variations, depending on the position inside the droplet, were related to the heterogeneous corrosion attacks of the aluminium surface quantified by AFM measurements. A modelling investigation is proposed to evaluate the distinct roles of alcalinisation, due to the oxygen reduction reaction (ORR), and the galvanic coupling between intermetallic particles and the surrounding matrix. It can be concluded that the former c…

Structural photoactivation of a full-length bacterial phytochrome

2016

Time-resolved x-ray solution scattering reveals the conformational signaling mechanism of a bacterial phytochrome.

Inhibitory effects and oxidation of 6-methylcoumarin, 7-methylcoumarin and 7-formylcoumarin via human CYP2A6 and its mouse and pig orthologous enzymes

2015

1. Information about the metabolism of compounds is essential in drug discovery and development, risk assessment of chemicals and further development of predictive methods. 2. In vitro and in silico methods were applied to evaluate the metabolic and inhibitory properties of 6-methylcoumarin, 7-methylcoumarin and 7-formylcoumarin with human CYP2A6, mouse CYP2A5 and pig CYP2A19. 3. 6-Methylcoumarin was oxidized to fluorescent 7-hydroxy-6-methylcoumarin by CYP2A6 (Km: 0.64-0.91 µM; Vmax: 0.81-0.89 min(-1)) and by CYP2A5 and CYP2A19. The reaction was almost completely inhibited at 10 µM 7-methylcoumarin in liver microsomes of human and mouse, but in pig only 40% inhibition was obtained with the…