Time progression and regional expression of brain oxidative stress induced by obstructive jaundice in rats.

Background: Obstructive jaundice induces oxidative changes in the brain parenchyma and plays significant role in clinical manifestations of hepatic encephalopathy. We aim to study the progression of the brain oxidative status over time and the differences of its pattern over the hemispheres, the brainstem and the cerebellum. We use an experimental model in rats and measuring the oxidative stress (OS) specific biomarkers protein malondialdehyde (PrMDA) and protein carbonyls (PrC = O).

Detection of superoxide radical in all biological systems by Thin Layer Chromatography.

The study presents a new method that detects O, via quantification of 2-hydroxyethidium (2-ΟΗ-Ε) as low as ∼30 fmoles by High-Performance Thin Layer Chromatography (HPTLC). The method isolates 2-ΟΗ-Ε after its extraction by the anionic detergent SDS (at 18-fold higher than its CMC) together with certain organic/inorganic reagents, and its HPTLC-separation from di-ethidium (di-Ε) and ethidium (Ε). Quantification of 2-OH-E is based on its ex/em maxima at 290/540 nm, and of di-E and E at 295/545 nm.

Age-related aqueous humor (AH) and lens epithelial cell/capsule protein carbonylation and AH protein concentration in cataract patients who have pseudoexfoliative diseases.

Purpose: The aim of this study is to investigate the age-correlation of oxidative stress (OS, assessed by the accumulative OS damage marker protein carbonyls) in aqueous humour (AH; together with protein concentration) and lens epithelial cells plus capsule (LECs/capsule) in patients with cataract (CAT), and also suffering from pseudoexfoliation syndrome (PEX), primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG).

Methods: AH samples from 78 male/female patients (21, 20, 19 and 18 with CAT, PEX, PXG, and POAG, respectively), and LECs/capsule samples from 104 male/female patients (34, 32, 18, and 20 with CAT, PEX, PXG and POAG, respectively) were collected during phacoemulsification CAT surgery. Average protein carbonyl concentrations were measured in patients grouped in 5-year age intervals (ranging from 56-60 to 86-90).

Protein carbonyl determination by a rhodamine B hydrazide-based fluorometric assay.

A new fluorometric assay is presented for the ultrasensitive quantification of total protein carbonyls, and is based on their specific reaction with rhodamine B hydrazide (RBH), and the production of a protein carbonyl-RBH hydrazone the fluorescence of which (at ex/em 560/585 nm) is greatly enhanced by guanidine-HCl. Compared to the fluorescein-5-thiosemicarbazide (FTC)-based fluorometric assay, the RBH assay uses a 24-fold shorter reaction incubation time (1 h) and at least 1000-fold lower protein quantity (2.5 µg), and produces very reliable data that were verified by extensive standardization experiments.

Protein and cell wall polysaccharide carbonyl determination by a neutral pH 2,4-dinitrophenylhydrazine-based photometric assay.

A new 2,4-dinitrophenylhydrazine (DNPH)-based photometric assay is developed for the quantification of carbonyls in protein samples from any biological source by protein carbonyl-DNPH hydrazone formation at acidic pH in the presence of denaturing urea, and subsequent hydrazone solubilization in the presence of SDS and stabilization from acid hydrolysis at pH 7.0. At this neutral (ntr) pH, interfering unreacted DNPH is uncharged and its thus increased hydrophobicity permits its 100% effective removal from the solubilizate with ethyl acetate/hexane wash.

Propranolol reduces systemic oxidative stress and endotoxemia in cirrhotic patients with esophageal varices.

Background: The aim of the study was to investigate the effect of propranolol on systemic oxidative stress and endotoxemia in patients with liver cirrhosis and clinically significant portal hypertension evidenced by the presence of esophageal varices.

Methods: Fourteen patients with liver cirrhosis and esophageal varices, not previously been treated with non-selective beta-blockers (NSBB), were prospectively started on propranolol and followed up for three months. Serum early and late lipid peroxidation products (lipid hydroperoxides [LOOH] and malondialdehyde [MDA], respectively), and endotoxin concentrations in peripheral blood were measured.

Ischemia-Reperfusion Injury of Sciatic Nerve in Rats: Protective Role of Combination of Vitamin C with E and Tissue Plasminogen Activator.

An ischemia/reperfusion injury of rat's sciatic nerve was experimentally developed. In this model, we measured the in vivo production of superoxide radical, as a marker of oxidative stress and the occludin expression as an indicator of blood-nerve barrier function and we examined potential protective innervations against these abnormalities. Right sciatic nerves of the animals underwent 3 h of ischemia followed by 7 days of reperfusion and were divided into three groups: ischemic, pretreated with vitamin C in conjunction with vitamin E and treated with tissue plasminogen activator.

BNN-20, a synthetic microneurotrophin, strongly protects dopaminergic neurons in the "weaver" mouse, a genetic model of dopamine-denervation, acting through the TrkB neurotrophin receptor.

Neurotrophic factors are among the most promising treatments aiming at slowing or stopping and even reversing Parkinson's disease (PD). However, in most cases, they cannot readily cross the human blood-brain-barrier (BBB). Herein, we propose as a therapeutic for PD the small molecule 17-beta-spiro-[5-androsten-17,2'-oxiran]-3beta-ol (BNN-20), a synthetic analogue of DHEA, which crosses the BBB and is deprived of endocrine side-effects.

Radiation-Driven Formation of Reactive Oxygen Species in Oxychlorine-Containing Mars Surface Analogues.

The present study demonstrates that γ-radiolyzed perchlorate-containing Mars soil salt analogues (in a CO atmosphere) generate upon HO wetting the reactive oxygen species (ROS) superoxide radical (O), hydrogen peroxide (HO), and hydroxyl radicals (OH). This study also validates that analogue radiolysis forms oxychlorine species that, in turn, can UV-photolyze to OH upon UV photolysis. This investigation was made possible by the development of a new assay for inorganic-origin O and HO determination and by the modification of a previous assay for soil OH.

Martian Superoxide and Peroxide O2 Release (OR) Assay: A New Technology for Terrestrial and Planetary Applications.

This study presents an assay for the detection and quantification of soil metal superoxides and peroxides in regolith and soil. The O2 release (OR) assay is based on the enzymatic conversion of the hydrolysis products of metal oxides to O2 and their quantification by an O2 electrode based on the stoichiometry of the involved reactions. The intermediate product O₂˙⁻ from the hydrolysis of metal superoxides is converted by cytochrome c to O2 and by superoxide dismutase (SOD) to ½ mol O2 and ½ mol H2O2, which is then converted by catalase (CAT) to ½ mol O2.

Evidence for photochemical production of reactive oxygen species in desert soils.

The combination of intense solar radiation and soil desiccation creates a short circuit in the biogeochemical carbon cycle, where soils release significant amounts of CO2 and reactive nitrogen oxides by abiotic oxidation. Here we show that desert soils accumulate metal superoxides and peroxides at higher levels than non-desert soils. We also show the photogeneration of equimolar superoxide and hydroxyl radical in desiccated and aqueous soils, respectively, by a photo-induced electron transfer mechanism supported by their mineralogical composition.

Intestinal mucosal proliferation, apoptosis and oxidative stress in patients with liver cirrhosis.

Background: Intestinal mucosal barrier dysfunction in liver cirrhosis and its implicated mechanisms is of great clinical importance because it is associated with the development of serious complications from diverse organs through promotion of systemic endotoxemia.

Aim: The present study was designed to investigate whether enterocytes' proliferation, apoptosis and intestinal oxidative stress are altered in the intestinal mucosa of patients with compensated and decompensated liver cirrhosis.

Material And Methods: Twelve healthy controls (group A) and twenty four cirrhotic patients at a compensated (n = 12, group B) or decompensated condition (n = 12, group C) were subjected to duodenal biopsy.

Method for the simultaneous determination of free/protein malondialdehyde and lipid/protein hydroperoxides.

A simple and sensitive method is presented for the simultaneous quantification (spectrophotometric and spectrofluorimetric) of the main lipid and protein peroxidation products after their initial fractionation: free malondialdehyde (FrMDA), protein-bound malondialdehyde (PrMDA), total hydroperoxides (LOOH), and protein hydroperoxides (PrOOH). FrMDA and PrMDA (released from proteins by alkaline hydrolysis) are measured after the reaction of MDA with thiobarbituric acid (TBA) under acidic conditions, by the specific fluorimetric quantification of the resulting MDA-(TBA)2 adduct chromophore. The measurement of LOOH and PrOOH is based on the reaction of Fe(3+) (resulting from the reaction of LOOH and PrOOH with Fe(2+)) with xylenol orange (XO) and the photometric quantification of the resulting XO-Fe complex.