A -acetylcysteine

IkB inhibitory protein kappa B lCAM-1 intercellular adhesion molecule 1 lL-1 interleukin-1 LDL low density lipoprotein MAPKs mitogen activated protein kinases MCP-1 macrophage chemotactic protein 1 M-CSF macrophage colony stimulating factor mmLDL minimally modified LDL NAC A-acetylcysteine NF-kB nuclear factor-kappa B oxLDL oxidised LDL PKC protein kinase C PMA phobol myristate acetate ROS reactive oxygen species TNF-a tumour necrosis factor alpha AM-1 vascular cell adhesion molecule 1... 

J6. Jebsen, S., Herlevsen, P., Knudsen, P Bud, M. I and Klausen, N. O., Antioxidant treatment with A/-acetylcysteine during adult respiratory distress syndrome A prospective randomized, placebo-controlled study. Cril. Care Med. 20,918-923 (1992). 

L. Weber, then at the Salk Institute in San Diego, was able to form high-energy thioesters from glycerinealdehyde and A-acetylcysteine. The reaction occurred under anaerobic conditions, at pH 7, in an aqueous solution of sodium phosphate. Of the aldehyde, 0.3% was converted to the lactoyl thioester per day of reaction (Weber, 1984). 

According to equation 7.15, at higher temperatures and low pH values (around pH 2). As already stated, Weber (1984) was able to carry out a thioester synthesis starting from glycerinealdehyde and A-acetylcysteine. 

A-acetylcysteine, a substance that cleaves sulfide bridges, has also been investigated, and although early reports claimed success, later studies showed no effect at all (B23, G10, H14, K39, S15). The differences in observations were probably induced by technical problems in the analysis of Lp(a) in the presence of a substance potent in the cleavage of S-S bonds. 

Although arteflene 5 is not a 1,2,4-trioxane, its mechanism of action is believed to be very similar to trioxanes dne to the presence of the peroxide bond. Indeed, when radioactive C-arteflene was incnbated with P. falciparum, several alkylated parasitic proteins were identified . The O Neill gronp carried out the first iron(II) degradation studies of arteflene using iron(II) chloride in aqneons acetonitrile they isolated enone 63a (in tandem with radical 63b) and diol 64a (Scheme 19A). The degradation with heme (generated from hemin chloride by A-acetylcysteine) was observed to be slower, but afforded the same products although in different ratio. 

Since depletion of tissue stores of sulfhydryl groups has been proposed to play an important role in nitrate tolerance, some investigators have administered sulfhydryl-containing compounds in an attempt to reverse or prevent the development of tolerance. The most commonly used agent is A-acetylcysteine (NAC), which is hydrolyzed in vivo to cysteine. Although some... 

The decomposition mode of the adducts has early been noticed to be associated with redox reactions (60,77), and is currently under scrutiny because of its great bioinorganic relevance. It has been shown that the reduction of NP to the EPR-active [Fe(CN)5NO]3 ion occurs in the reaction with cysteine, which is oxidized to cystine (60). In this reaction, NP showed to behave catalytically with respect to the autoxidation of cysteine to cystine, provided enough oxygen was present. A recent kinetic and mechanistic study has thrown more light on the complex mechanistic details comprising the decompositions of the red adducts formed by NP with cysteine, A-acetylcysteine, ethyl cysteinate, and glutathione (120). Under conditions of excess of NP, in anaerobic medium, the reversible adduct formation step is shown by Eq. (26) ... 

Mucomyst (Apothecon) Acetylcysteine (A-acetylcysteine) Solution, 10% or 20% as salt sodium May contain EDTA... 

Buchter, A., Peter, H. Bolt, H.M. (1984) A -Acetylcysteine as an antidote in accidental acrylonitrile poisoning. Int. Arch, occup. environ. Health, 53, 311-319 (in German)... 

No studies were available on the disposition of benzotrichloride, benzal chloride or benzoyl chloride. Benzyl chloride is rapidly absorbed and distributed from the gastrointestinal tract. Excretion is mainly in urine as S -benzyl-A-acetylcysteine, benzyl alcohol and benzaldehyde. 

Kim, D.H. Guengerich. F.P. (1989) Excretion of the mercapturic acid 5 -[2-(A7-guanyl)ethyl]-A-acetylcysteine in urine following administration of ethylene dibromide to rats. Cancer Res., 49, 5843-5847... 

Treatment of animals with A-acetylcysteine, a precursor of glutathione, protects animals against acetaminophen-induced hepatic necrosis, possibly by reducing covalent binding to tissue macromolecules. However, depletion of glutathione potentiates covalent binding and hepatotoxicity. 

Analytical methods have been reported for unchanged agent and six of the urinary excretion products described above. These are TDG, TDGO, the bis A-acetylcysteine conjugate (1), two 3-lyase metabolites (2) and (3), and the guanine adduct (6). These methods have been applied to animal and/or human exposures to sulfur mustard. 

MS/MS, was negative for the bis-(A-acetylcysteine) conjugate (1). Very recently, these samples have been reanalyzed using the LC/ESI/MS/MS method reported in Section 2.2.5. Low concentrations ( 1 ng/ml) were detected in both samples (31). These are lower than would have been expected from animal studies, but the samples had been stored frozen for 12 years and thawed and refrozen on several occasions. 

Halogen atoms in nucleosides can be replaced photochemically by sulphur as has been demonstrated in the photoinduced alkylthiolation of halogenated purine nucleosides433,749, in the synthesis of 2-(methylthio)adenosine from 2-iodoadenosine750 and in the photochemical formation of a cysteine-uracil adduct from 5-bromouracil and A-acetylcysteine methyl ester435. Photochemical synthesis of phosphonopyrimidine and phosphonopurine nucleosides by reaction of bromonucleosides with triethyl phosphite has also been reported751. 

---