Acid damage detection

Determination of oxidized amino acids in urine is usually performed by isotope dilution gas chromatography-mass spectrometry (L9). DOPA is estimated by HPLC separation of acid protein hydrolysates with fluorescence detection (excitation 280 nm, emission at 320 nm) (A15). Other methods are based on borate-hydrochloric acid difference spectroscopy (this method suffers interference from tyrosine and tryptophan) (W2), derivatization of DOPA with nitrite and subsequent coulometric determination (W3), and fluorometric detection after derivatization with ethylenediamine (A15). 3-Hydroxylysine is quantitated by HPLC with 9-fluorenylmethyl chloroformate precolumn derivatization (M25) of amino acids obtained by gas-phase hydrolysis of proteins (F21). Other general methods to detect amino acid damage are mass spectometry methods applied to protein hydrolysates, such as tandem mass spectrometry (F6). 

Detection of acid damage with Fehling s solution... 

The DNA-electrochemical biosensor is a very good model for evaluation of nucleic acid damage, and electrochemical detection is a particularly sensitive and selective method for the investigation of specific interactions [2-6]. The interpretation of electrochemical data can contribute to elucidation of the mechanism by which DNA is oxidatively damaged by hazardous compounds, in an approach to the real action scenario that occurs in the living cell and without using animal tests. 

Sawa, T., Tatemichi, M., Akaike, T., Barbin, A., and Ohshima, H. (2(X)6). Analysis of urinary 8-nitroguanine, a marker of nitrative nucleic acid damage, by high-performance hq-uid chromatography-electrochemical detection coupled with immunoafhnity purification Association with cigarette smoking. Free Radic. Biol. Med. 40,111-720. 

Alpha-l-antiprotease (ai-AP) limits tissue damage arising from the actions of the leucocyte protease, elastase (Carrell and Travis, 1985), and there is much evidence available for the oxidative inactivation of this protein by oxygen-derived free-radical species and hypochlorous acid/hypochlorite anion (HOCl/OCP). The mechanism of this inactivation appears to involve the oxidation of a critical methionine residue (Met-358) to its corresponding sulphoxide and methionine sulphoxide has been detected in ai-AP samples isolated from the lungs of cigarette smokers (Carp et al., 1982) and rheumatoid synovial fluids (Wong and Travis, 1980). 

This chapter will review some recently completed studies on the long-term effects of MDMA in nonhuman primates. The goals of these studies were to (1) determine if the neurotoxic effects of MDMA, which have been well documented in the rodent (see below), generalize to the primate (2) compare the relative sensitivity of primates and rodents to the neurotoxic effects of MDMA (3) ascertain if the toxic effects of MDMA in the monkey are restricted to nerve fibers (as they are in the rat), or if they involve cell bodies as well (4) evaluate how closely toxic doses of MDMA in the monkey approximate those used by humans and (5) examine whether 5-hydroxyindoleacetic acid (5-HIAA) in the cerebrospinal fluid (CSF) can be used to detect MDMA-induced serotonergic damage in the CNS of primates. Before presenting the results of these studies, previous results in the... 

A specific approach for the measurement of base damage to DNA involves the hydrolysis of DNA into monomeric units. Acidic hydrolysis leads to the release of bases while enzymatic treatment yields nucleosides. The resulting mixture of lesions together with the overwhelming presence of normal bases or nucleosides is resolved by chromatography. The targeted damage is then quantified by use of specific detection systems. 

A pickle is a food preserved in vinegar (ethanoic acid). Pickles generally have a sharp, acidic flavour in consequence of the acid preservative. Many systems - especially living cells - require their pH to be maintained over a very restricted range in order to prevent catastrophic damage to the cell. Enzymes and proteins denature, for example, if the pH deviates by more than a fraction. Traces of the food we eat are readily detected in the blood quite soon after eating, so why does the concentration in the blood remain constant, rather than dropping substantially with the additional acid in our diet ... 

---