PubMed · 156620
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
C D Calnan. 1979. Chloracetophenone (CS) dermatitis.. https://doi.org/10.1111/j.1600-0536.1979.tb04847.x
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
A library of novel dipeptide-analogue ligands based on the combination of tert-butoxycarbonyl(N-Boc)-protected alpha-amino acids and chiral vicinal amino alcohols were prepared. These highly modular ligands were combined with [[RuCl(2)(p-cymene)](2)] and the resulting metal complexes were screened as catalysts for the enantioselective reduction of acetophenone under transfer hydrogenation conditions using 2-propanol as the hydrogen donor. Excellent enantioselectivity of 1-phenylethanol (up to 98 % ee) was achieved with several of the novel catalysts. Although most of the ligands contained two stereocenters, it was demonstrated that the absolute configuration of the product alcohol was determined by the configuration of the amino acid part of the ligand. Employing ligands based on L-amino acids generated S-configured products, and catalysts based on D-amino acids favored the formation of the R-configured alcohol. The combination N-Boc-L-alanine and (R)-phenylglycinol (Boc-L-Ab) or its enantiomer (N-Boc-D-alanine and (S)-phenylglycinol, Boc-D-Aa) proved to be the best ligands for the reduction process. Transfer hydrogenation of a number of aryl alkyl ketones were evaluated and excellent enantioselectivity, up to 96 % ee, was obtained.
Human neutrophils differ from other cells by containing high amount of IkappaBalpha in the nucleus, and this increased nuclear IkappaBalpha accumulation is associated with the inhibition of NFkappaB activity and increased apoptosis. However, the mechanisms regulating NFkappaB activation and IkappaBalpha degradation in human neutrophils are little understood. The objective of this study was to provide a further insight into the mechanisms regulating NFkappaB activity and IkappaBalpha degradation in human neutrophils. We show that okadaic acid (OA), an inhibitor of protein phosphatases PP1 and PP2A, induces sustained activation of NFkappaB and degradation of the nuclear IkappaBalpha, and increases interleukin-8 expression in the neutrophils. Furthermore, inhibitors of protein kinase C-delta (PKCdelta) and IkappaB kinase (IKK) inhibit the OA-induced activation of NFkappaB. Collectively, our results indicate that in human neutrophils, the sustained activation of NFkappaB is regulated by a continuous phosphorylation and degradation of the nuclear IkappaBalpha.
Protein kinases C (PKCs) are a family of isoenzymes sensitive to oxidative modifications and involved in the transduction signal pathways that regulate cell growth. As such, they can act as cellular sensors able to intercept intracellular redox changes and promote the primary adaptive cell response. In this study, we have demonstrated that PKC isoforms are specifically influenced by the amount of intracellular glutathione (GSH). The greatest GSH depletion is associated with a maximal reactive oxygen species (ROS) production and accompanied by an increase in the activity of the delta isoform and a concomitant inactivation of alpha. ROS generation induced early morphological changes in GSH-depleted neuroblastoma cells characterized, at the intracellular level, by the modulation of PKC-delta activity that was involved in the pathway leading to apoptosis. When cells were pretreated with rottlerin, their survival was improved by the ability of this compound to inhibit the activity of PKC-delta and to counteract ROS production. These results define a novel role of PKC-delta in the cell signaling pathway triggered by GSH loss normally associated with many neurodegenerative diseases and clinically employed in the treatment of neuroblastoma.