Search results for "Reduction"
showing 10 items of 2058 documents
Chromatographic and mass spectrometric characteristics of 20-dihydroaldosterone.
1992
The 20 alpha-reduced derivative of aldosterone, 20 alpha-dihydroaldosterone, was needed as reference compound in order to continue the studies on 18-hydroxylation in the Y-1 adrenal cell line. It was obtained by reduction of aldosterone with sodium borohydride. Analysis of the products of the reaction as methoxime trimethylsilyl (MO-TMS) derivatives by gas chromatography (GC) and GC-mass spectrometry (GC-MS) showed three possible forms of the compound. Their identification was confirmed by comparison with the products obtained by stereospecific reduction of aldosterone using 3 alpha,20 beta-hydroxysteroid dehydrogenase. Chromatographic behavior and mass spectra are given for the three forms…
Inhibitor-Induced Dimerization of an Essential Oxidoreductase from African Trypanosomes
2018
Trypanosomal and leishmanial infections claim tens of thousands of lives each year. The metabolism of these unicellular eukaryotic parasites differs from the human host and their enzymes thus constitute promising drug targets. Tryparedoxin (Tpx) from Trypanosoma brucei is the essential oxidoreductase in the parasite's hydroperoxide-clearance cascade. In vitro and in vivo functional assays show that a small, selective inhibitor efficiently inhibits Tpx. With X-ray crystallography, SAXS, analytical SEC, SEC-MALS, MD simulations, ITC, and NMR spectroscopy, we show how covalent binding of this monofunctional inhibitor leads to Tpx dimerization. Intra- and intermolecular inhibitor-inhibitor, pro…
Oxidation of carbidopa by tyrosinase and its effect on murine melanoma
2009
Oxidation of the anti-Parkinsonian agent carbidopa by tyrosinase was investigated. The products of this reaction were identified as 3-(3,4-dihydroxyphenyl)-2-methylpropanoic acid and 6,7-dihydroxy-3-methylcinnoline. These results demonstrate that after oxidation of the catechol moiety to an o-quinone either a redox exchange with the hydrazine group or a cyclization reaction occur. The cyclization product underwent additional oxidation reactions leading to aromatization. The cyclization reaction is undesired in the case of hydrazine-containing anti-melanoma prodrugs and will have to be taken into account in designing such compounds. Carbidopa was tested against B16(F10) melanoma cells in cul…
Indirect oxidation of the antitumor agent procarbazine by tyrosinase—Possible application in designing anti-melanoma prodrugs
2008
The interaction of tyrosinase with the anticancer drug procarbazine has been investigated. In the presence of the enzyme alone no oxidation of this dialkylhydrazine above the background level was observed. However, when phenolic substrates (4-tert-butylcatechol or N-acetyl-l-tyrosine) were included in the reaction mixture, procarbazine was rapidly degraded. Oxygen consumption measurements showed that in a mixture both the phenolic substrate and the drug were oxidized. The major product of procarbazine degradation was isolated and identified as azoprocarbazine, the first active metabolite of this drug detected in previous in vivo and in vitro studies. This indirect oxidation of the hydrazine…
The experimental herbicide UKJ72J is an inhibitor of succinate oxidation in plant mitochondria
1983
not received UKJ72J Herbicide Thiopyrimidine Plant mitochondria Inhibitor Succinate oxidation
ENTREACTO / ENTR?ACTE Un film / A Film Chopin y los Sand, amor a cuatro bandas. Aproximación a la esfera privada de Fryderyk Chopin a partir de la pe…
2021
Two centuries later, the legend Chopin-Sand continues to supply the collective imaginary with vague readings, where historical truthfulness, let alone musical truth, is often contingent on the literary. The much discussed and bellicose romance between the Polish composer and the French novelist, George Sand, tends to some reductionism and evades an obvious reality: Fryderyk Chopin meets George Sand when she was already the mother of two children. This circumstance suggests reformulating certain romantic stereotypes. Jerzy Antczak?s biographical film Pragnienie Mi?o?ci (Chopin: Desire for Love, 2002) does not overlook this detail and makes it one of its narrative axes. The relationship betwe…
Reduction of tris(benzene-1,2-dithiolate)molybdenum(VI) by hydroxide ions in dry tetrahydrofuran solution.
2001
Tris(benzene-1,2-dithiolate)molybdenum(VI) reacts rapidly and quantitatively with tetrabutylammonium hydroxide to yield the corresponding Mo(V) and Mo(IV) complexes and hydrogen peroxide; the reaction has been executed in dry tetrahydrofuran where the reaction rate shows a fair dependence on complex and OH2 concentrations. Cervilla Avalos, Antonio, Antonio.Cervilla@uv.es ; Perez Pla, Francisco, Francisco.Perez@uv.es ; Llopis Jover, Elisa, Elisa.Llopis@uv.es
Residual out-of-plane capacity of infills damaged by in-plane cyclic loads
2020
Abstract During earthquakes, infills are subjected to In-Plane (IP) and Out-Of-Plane (OOP) actions. In the case of strong earthquakes, infills may progressively change their mechanical behavior resulting in a reduction of IP and OOP stiffness and strength. Recent earthquakes have proved that the OOP collapse of infills is a diffused mechanism also for buildings designed to resist seismic events in agreement to the most modern codes. This is potentially a very dangerous event with risk for human health. The strong interaction between IP and OOP behavior of infills traduces in a progressive reduction of the OOP strength. The IP damaging loads may cause a loss of the OOP capacity not predicted…
Antioxidant betalains from cactus pear (Opuntia ficus-indica) inhibit endothelial ICAM-1 expression.
2004
It has been suggested that some pigments would have antioxidant properties and that their presence in dietary constituents would contribute to reduce the risk of oxidative stress–correlated diseases. Among others, inflammatory response depends on redox status and may implicate oxidative stress. Vascular endothelial cells are a direct target of oxidative stress in inflammation. We have tested the impact of the free radical scavenger and antioxidant properties of betalains from the prickle pear in an in vitro model of endothelial cells. Here we show the capacity of betalains to protect endothelium from cytokine- induced redox state alteration, through ICAM-1 inhibition. KEYWORDS: endothelial …
Bicommutants of reduced unbounded operator algebras
2009
The unbounded bicommutant $(\mathfrak M_{E'})''$ of the {\em reduction} of an O*-algebra $\MM$ via a given projection $E'$ weakly commuting with $\mathfrak M$ is studied, with the aim of finding conditions under which the reduction of a GW*-algebra is a GW*-algebra itself. The obtained results are applied to the problem of the existence of conditional expectations on O*-algebras.