N-acetyl cysteine, NAC

N-acetyl cysteine (NAC) in animal studies, NAC administered intratracheally 45-60 min after high-dose phosgene exposure significantly reduced development of pulmonary edema (15,34). The appropriate dose for humans would be 20 mL of a 20% NAC solution administered via nebulizer. However, there is no evidence for using this regimen in humans, and the FDA has not approved its use for prophylactic treaunent of phosgene exposure (34). 

In more recent studies, the effect of ascorbate was investigated in latently infected cell lines that had been stimulated with tumor promoter or inflammatory cytokine to trigger virus production (Harakeh and Jariwalla, 1994, and unpublished data). Pretreatment of cells with 100-300 jLg/ml ascorbate followed by cell stimulation with phorbol ester (PMA) or cytokine (TNF-a) resulted in dose-dependent suppression of virus activation. Unlike N-acetyl cysteine (NAC), which suppressed cytokine-stimulated HIV expression through inhibition of transcriptional activation by NF-kB, ascorbate seemed to have no effect on the activity of this transcription factor. AZT, a known inhibitor of de novo infection, had no effect on virus production in either unstimulated chronically infected cells or in stimulated latently infected cells (Harakeh and Jariwalla, 1994). 

Cysteine is a principal source of sulfur in the diet, which is necessary for the production of coenzyme A and taurine. Cysteine is also ntdized in PS, espeeially in the formation of hair and skin. It supports wound healing and stimulates white blood cell activity. The N-acetyl derivative of cysteine is N-acetyl cysteine (NAC), which is more stable and is the preferred form of cysteine for oral ingestion and infusion. NAC has been shown to protect the liver from the effects of alcohol, acetaminophm, and cancer drugs.NAC provides significant free radical protection and may be beneficial in reducing oxidative damage from exercise. ... 

Figure 4 Metal catalyzed oxidation (MCO) in vitro. Bovine lens water soluble protein (BLPS) was incubated with MGO or ASA with or without catalase (CAT) for 7 days. A and C The 6-hydroxynorleucine and 2-AAA levels were determined by GC/MS (B) the H2O2 was determined daily during incubation measured by Amplex-Red assay. D Oxidized poly-L-lysine was incubated with H2O2 with or without N-acetyl-cysteine (NAC).

Figure 8. Reverse phase high pressure liquid chromatogram of aflatoxin (AFB- ) and its N-acetyl-cysteine derivative (NAC-AFB ). Actual elution times in minutes are shown near each peak. Att = attenuation (Friedman et al., 1982d).

Abbreviations used in this chapter AZT, 3 -azidothymidine CD, cluster of differentiation CHS, Chediak-Higashi syndrome Con A, concanavalin-A EAE, experimental allergic encephalomyelitis HIV, human immunodeficiency virus HTLV-1, human T-cell leukemia virus-1 IL, interleukin INF, interferon NAC, N-acetyl cysteine NF-kB, neurotrophic factor-k beta PBMC, peripheral blood mononuclear cells PM A, phorbol 12-myristate 13-acetate PMN, polymorphonuclear neutrophil RT, reverse transcriptase TNF-2 tumor necrosis factor alpha. 

OPA in combination with chiral thiols is one method used to determine amino acid enantiomers. A highly fluorescent diastereomeric isoindole is formed and can be separated on a reverse-phase column. Some of these chiral thiols include N-acetyl-L-cysteine (NAC), N-tert-butyloxy-carbonyl- L-cysteine (Boc-L-Cys), N-isobutyryl- L-cysteine (IBLC), and N-isobutyryl- D -cysteine (IBDC). Replacing OPA-IBLC with OPA-IBDC causes a reversal in the elution order of the derivatives of D- and L-amino acids on an ODS column (Hamase et al., 2002). Nimura and colleagues (2003) developed a novel, optically active thiol compound, N-(tert-butylthiocarbamoyl)- L-cysteine ethyl ester (BTCC). This reagent was applied to the measurement of D-Asp with a detection limit of approximately 1 pmol, even in the presence of large quantities of L-ASP. 

Unithiol and succimer increase urine mercury excretion following acute or chronic elemental mercury inhalation, but the impact of such treatment on clinical outcome is unknown. Dimercaprol has been shown to redistribute mercury to the central nervous system from other tissue sites, and since the brain is a key target organ, dimercaprol should not be used in treatment of exposure to elemental or organic mercury. Limited data suggest that succimer, unithiol, and N- acetyl-L-cysteine (NAC) may enhance body clearance of methylmercury. 

SYNS l-a-ACETAMIDO-P-MERCAPTOPROPIONIC ACID ACETEIN ACETYLCYSTEINE N-ACETYLCYSTEINE N-ACETYL-N-CYSTEINE N-ACETYL-l-CYSTEINE (9CI) N-ACETYL-3-MERCAPTO-AL.ANINE AIRBRON BRONCHOL-YSIN FLUIMUCETIN FLULMUCIL FLUMICIL INSPIR MERCAPTURIC ACID (R)-MERCAP-TURIC ACID MUCOLYTICUM MUCOLYTICUM LAPPE MUCOMYST MUCOSOLVIN NAC NAC-TB NSC-111180 PARVOLEX RESPAIRE... 

N-Acetyl-L-cysteine (NAC) is a natural sulfur-containing compound that is produced in living organisms from the amino acid cysteine. It is involved in the intracellular synthesis of a chemical called glutathione (or GSH). Cells (particularly liver cells)... 

HPLC-FD High-performance liquid chromatography combined with fluorescence detection has been used for the first analyses of nucleobases in carbonaceous chondrites (/5). More recently, pre-column derivatization of amino acid with o-phthaldialdehyde/N-acetyl-L-cysteine (OPA/NAC) has allowed the detection and enantiomeric separation of a few pmol of amino acids 16),... 

Synonyms. N-Acetyl-L-cysteine (NAC) L-Cysteine, N-acetyl- Mucomyst. 

Isoindoles of o-phthalaldehyde (OPA)/N acetyl-L-cysteine (NAC) are commonly used for detection of amino acids (RiCH(COOH)NH2) RPLC. A particular hydrophobicity scale was established with the retention data of these derivatives in mobile phases of SDS at pH 3, using the glycine derivative as a reference [20], Linear relationships were obtained between the ratios of log k of each amino acid derivative to log k of the glycine derivative (which was called quantitation of hydrophobicity index, QH), and log Pq for the Ri substituents (tTri). 

Because of the different and low stability of the isoindoles obtained from the reaction of AAs with OPA/MCE reagent, alternative precolumn derivat-izations reagents, such as 3-mercaptopropionic acid (MPA) and several N-alkyl-L/o-cysteines, were proposed. The OPA/MPA and OPA/N-acetyl-L-cysteine (NAC) reagents provide more stable isoindoles compared to those formed with the OPA/MCE, and the optical resolution of enantiomeric AAs with the OPA/NAC, as well as with further N-alkyl-L/o-cysteine reagents, have opened a new area in separation of AA enantiomers. Due to robotic autosamplers, which provide excellent reproducibility even for moderately quantitative interactions, most AA analyses are performed with the OPA derivative. The unexplainable contradictions of this most popular process - relating to the particularly low stability of the OPA derivatives of six very important AAs (glycine, y-aminobutyric acid (GABA), jS-alanine,... 

N-Acetyl-l-cysteine (NAC), another significant precursor of the GSH biosynthesis, has broadly been used as effective antioxidant in a form of nutritional supplement (Soloveva M. E et al 2007, Thibodeau P. A., et al 2001). At low concentrations, it is a powerful protector of a-l-antiproteinase against the enzyme inactivation by HOCl. NAC reacts with HO radicals and slowly with H O however, no reaction of this endobiotics with superoxide anion radical was detected [88]. 

Table 2 Advances in the LC of precolumn derivatized AAs, obtained with OPA/MCE, OPA/ethanethiol, OPA/mercaptopropionic acid, OPA/AZ-acetyl-i-cysteine, with OPA/N-isobutyril-i/D-cysteine, and with OPA/MPA/fluorenylmethylchloroformate (OPA/ET OPA/MPA OPA/NAC OPA/NIBC OPA/MPA/FMOC)... 

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