1,721,063 research outputs found
4-Hydroxynonenal and other aldehydes produced in the liver in vivo after bromobenzene intoxication
No full text4-Hydroxynonenal (4-HNE) has been identified as one of the most reactive products in a series of toxic aldehydes originating from lipid peroxidation of cellular membranes. The possibility that this aldehyde plays a role as one of the mediators of the cellular injury induced by pro-oxidants is currently investigated. Mice intoxicated with bromobenzene showed levels of lipid peroxidation in the liver that exceed those induced by hepatotoxic haloalkanes CCl4 and BrCCl3. Hence, we have searched for the presence of 4-HNE and other lipid peroxidation products in the liver of bromobenzene-poisoned mice. We looked for 4-HNE in liver extracts as either free aldehyde or its 2,4-dinitrophenylhydrazone derivative. Using thin-layer chromatography (TLC) and high pressure liquid chromatography (HPLC) we obtained well resolved peaks, corresponding to the standard aldehyde or its 2,4-dinitrophenylhydrazone derivative, respectively. 2,4-dinitrophenylhydrazone derivatization was also used to determine the total carbonyl content in the liver of the intoxicated animals. Three fractions of hydrazones, according to their different polarity (“polar”; “non-polar carbonyls, fraction I”; and “non-polar carbonyls, fraction II”), were obtained using TLC. The UV-visible spectra were recorded for quantitative evaluation. Further fractionation of “non-polar carbonyls, fraction II” provided a fraction containing several alkanals and alk-2-enals, which were analyzed and identified by HPLC. Furthermore, protein bound carbonyls were determined in the liver of the intoxicated animals. © 1986, SAGE Publications. All rights reserved
Opposite impact of inflammation and oxidative stress on vascular GGT activity
No full textPurpose. Gamma-glutamyltransferase (GGT) is a cell surface enzyme from the Meister cycle that catalyzes the first step in the catabolism of glutathione (GSH) and its derivative S-nitroso-glutathione (GSNO), thus allowing for both the recovery of precursor aminoacids and – with regard to GSNO – the release of nitric oxide (NO). Recent studies indicate that increased levels of GGT activity in the serum are correlated with increased cardiovascular morbidity/mortality, including atherosclerosis or hypertension, two contexts of vascular wall inflammation and oxidative stress [1]. However lesser is known on GGT activity inside the vascular wall. Our aim was to evaluate GGT activity in cells and tissue from the vascular wall in several models of inflammation and oxidative stress.
Methods. GGT activity (quantified using L-γ-glutamyl-p-nitroanilide) and intracellular GSH concentrations (measured by 2,3-naphtalene dicarboxaldeide) were measured in (i) smooth muscle cells isolated from rat aortic wall (A10 line) stimulated either with LPS (20 μg/ml, 24 h 37°C) or 2,2'-azobios(2-amidinopropane) dihydrochloride (AAPH; 50mM, 2 h 37°C) to mimic inflammation or oxidative stress respectively, and (ii) in aorta homogenates from male Spontaneously Hypertensive Rats (SHR) compared to their counterparts WKY normotensive Wistar Kyoto rats. In human atherosclerotic carotid plaques, GGT expression was assessed by SDS-PAGE analysis in homogenates, using macrophages infiltration as marker of inflammation.
Results. In human atherosclerotic plaques homogenates, the presence of a high-molecular weight GGT similar to that expressed by monocytes/macrophage was observed, with the highest GGT expression in presence of high vs. low macrophage infiltration (score 2: 5-10%, 3: >10% vs. 1: <0.5%). GGT activity increased in the cultured cell model of inflammation (Table 1), while it decreased in the cell and tissue models of oxidative stress in parallel with the decrease in GSH content.
Conclusion. We planned to further evaluate the possible modulation between activated macrophages and promotion of pro-atherogenic process in SMC. Future experiments may also help to fully elucidate the mechanisms of GGT release and/or activity and its role during inflammation and/or oxidative stress.
Keywords: Gamma-glutamyltransferase, inflammation, oxidative stress, atherosclerosis, smooth muscle cells
Bibliography:
1. Pompella A, Emdin M, Passino C, Paolicchi A. The significance of serum gamma-glutamyltransferase in cardiovascular diseases. Clin. Chem. Lab. Med., 2004, 42: 1085-91
Histochemical detection of lipid peroxidation in the liver of bromobenzene-poisoned mice
No full textThe possibility of detecting lipid peroxidation histochemically was investigated in liver tissue in vivo, in conditions in which the process has been demonstrated by biochemical methods. The technique was based on the detection of aldehyde functions with the use of the Schiff's reagent. The study was carried out on bromobenzene-intoxicated mice, which generally exhibit levels of lipid peroxidation considerably higher than those observed in the case of other hepatotoxins. Liver sections from control animals were unstainable by the reagent, while sections from bromobenzene-poisoned mice showed a purple stain of various intensity, unhomogeneously distributed, sometimes with a mediolobular localization. Microphotometric measurements were performed at 565 nm by means of a computer-controlled microscope photometer. The ratios of Schiff-positive area relative to total section area, as well as the total extinctions referred to 100 sq Î1⁄4 of the sections, showed a high correlation with the corresponding hepatic contents of malonic dialdehyde, chosen as biochemical index of lipid peroxidation. In vitro studies in which liver sections were incubated in the presence of NADPH-Fe2+, showed a Schiff positivity which increased with the incubation time, confirming the reliability of the histochemical method. Another procedure, based on the use of 2-OH-3-naphtoic acid hydrazide coupled with fast blue B, was also developed and proved to be possibly more sensitive than Schiff's reagent in the detection of lipid peroxidation in liver tissue
Glutathione depletion, lipid peroxidation, and the antecedents of ferroptosis: What about cellular calcium?
No full textGlutathione depletion, lipid peroxidation, and the antecedents of ferroptosis: What about cellular calcium ?
No full text
Serum gamma-glutamyltransferase as a risk factor of ischemic stroke might be independent of alcohol consumption.
No full textGLUCOSE-6-PHOSPHATE DEHYDROGENASE IS HIGHER IN THE OLFACTORY BULB THAN IN OTHER BRAIN AREAS
No full text- …
