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Workers involved in mining activities are exposed to crystalline silica, which leads to constant pulmonary inflammatory reactions and severe oxidative damage, resulting in silicosis. In this work, we aimed to evaluate inflammatory and oxidative stress parameters as potential early biomarkers of effect to assess crystalline silica toxicity in workers who had occupational exposure during mining. We enrolled 38 workers exposed to crystalline silica (WECS), 24 individuals with silicosis (IWS), and 30 occupationally unexposed workers (OUW), a total of 92 participants. The WECS were divided into 2 groups, according to the time of exposure: 19 workers with 1-15 years of occupational exposure (WECS I) and 19 workers with >16 years of occupational exposure (WECS II). The inflammatory parameters assessed were L-selectin, β-2 integrin, and intercellular adhesion molecule-1 (ICAM-1) surface protein expression in lymphocytes and monocytes, complement C3 and C4, high sensitivity C-reactive protein (hsCRP), and adenosine deaminase (ADA) in serum. Plasma levels of malondialdehyde (MDA) and serum levels of vitamin C were determined as biomarkers of oxidative stress. Biochemical and hematological parameters were also investigated. L-selectin surface protein expression was significantly decreased in the WECS II group (p < 0.05), indicating the importance of this immune system component as a potential marker of crystalline-silica-induced toxicity. The MDA levels were significantly increased in the WECS I, WECS II, and IWS groups compared to the OUW group (p < 0.05). Vitamin C levels were decreased, while C3, hsCRP, ADA, and aspartate aminotransferase (AST) levels were increased in the IWS group compared to the OUW group (p < 0.05). Glucose and urea levels were significantly higher in the WECS I, II, and IWS groups compared to the OUW group (p < 0.05). Negative partial association was found between L-selectin and time of exposure (p < 0.001), supporting the relevance of this biomarker evaluation in long-term exposure to crystalline silica. Significant associations were also observed among inflammatory and oxidative stress biomarkers. Therefore, our results demonstrated the relevance of L-selectin as a potential peripheral biomarker for monitoring crystalline silica-induced toxicity in miners after chronic exposure, before silicosis has developed. However, more studies are necessary for better understanding of the use L-selectin as an early biomarker in exposed workers., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Background: Sestrins (Sesns) family, which including three members Sesn1, Sesn2 and Sesn3, is known as stress-inducible proteins and participate in multiple diseases via regulating oxidative stress, inflammatory response and cell apoptosis. The present study aimed to investigate the plasma levels and the clinical significance of Sesns in patients with coronary artery disease (CAD)., Methods: In the case-control study, 119 CAD patients, including stable angina pectoris (SAP, n=44), unstable angina pectoris (UAP, n=41) and acute myocardial infarction (AMI, n=29) were included. Patients with chest pain syndrome but excluded CAD (n=35) were enrolled as control. Plasma levels of Sesn1, Sesn2, Sesn3, superoxide dismutase (SOD) and malondialdehyde (MDA) in all patients were measured and analyzed., Results: Compared with control group, plasma levels of Sesn1, Sesn2 and Sesn3 were significantly increased in patients with SAP, UAP and AMI. In addition, a significant lower SOD levels and higher MDA levels were observed in CAD patients, Sesn1/2/3 levels were negatively correlated with SOD levels and positively correlated with MDA levels. Gensini Score were positively correlated with Sesn1/2/3 levels and MDA levels, whereas negatively correlated with SOD levels. Furthermore, as the main risk factors for CAD, the elderly and obesity increased plasma Sesn2 levels, diabetes increased both plasma Sesn2 and Sesn3 levels., Conclusions: Our study was the first to report that the plasma Sesns levels were increased in CAD patients and positively related to the severity of coronary heart disease. Although the exact mechanisms of Sesns in CAD are still unknown, alleviated oxidative stress may be the possible reasons., (Copyright © 2017. Published by Elsevier B.V.)

Background: The circadian rhythm, as part of a broad time structure (chronome) of lipid peroxides and antioxidant defense mechanisms may relate to prevention, efficacy and management of preventive and curative chronotherapy., Methods: Fifty newly diagnosed patients with peptic ulcers, 30-45 years of age, and 60 age-matched clinically healthy volunteers were synchronized for one week with diurnal activity from about 06:00 to about 22:00 and nocturnal rest. Breakfast was served around 08:30, lunch around 13:30 and dinner around 20:30. Drugs known to affect the free-radical systems were not taken. Blood samples were collected at 6-hour intervals for 24h under standardized, presumably 24-hour synchronized conditions. Plasma lipid peroxides, in the form of malondialdehyde (MDA), blood superoxide dismutase (SOD), glutathione peroxide (GPx), glutathione reductase (GR), catalase (CAT) activities, and serum total protein, albumin, ascorbic acid, total serum cholesterol, and HDL-cholesterol concentrations were determined., Results: By population-mean cosinor analysis, a marked circadian variation was demonstrated for all variables in healthy subjects and in ulcer patients (p<0.001). As compared to controls, patients had a lower MESOR of MDA, SOD, GPx, GR, ascorbic acid, and HDL-C. They also had smaller circadian amplitude of SOD, CAT, GPx, GR, ascorbic acid, T-C, and HDL-C, but larger circadian amplitude of MDA and albumin. As compared to healthy subjects, the circadian acrophase of ulcer patients occurred later for MDA and GR and earlier for GPx., Conclusion: Mapping circadian rhythms, important chronome components that include trends with age and extra-circadian components characterizing antioxidants and pro-oxidants, is needed for exploring their putative role as markers in the treatment and management of peptic ulcers., (Copyright © 2015. Published by Elsevier B.V.)

Background: Although increased circulating levels of malondialdehyde-modified low-density lipoprotein (MDA-LDL) are associated with coronary artery disease (CAD), there is no direct evidence that increased MDA-LDL is a prognostic factor for CAD., Methods: Forty-two patients (20 diabetic and 22 non-diabetic patients) who underwent percutaneous coronary intervention (PCI) were enrolled, and their baseline MDA-LDL levels were determined by immunoassay. Follow-up coronary angiography was performed at 2 to 7 months post-PCI. The patients were then divided into 2 groups, with in-stent restenosis (ISR) (n=13) and without ISR (n=29), and the baseline MDA-LDL levels were compared. We also studied 34 diabetics with CAD for up to 57 months until the onset of the next coronary event., Results: In the diabetic patients, the mean MDA-LDL level was significantly higher in those with ISR than in those without ISR (151+/-61 vs. 90+/-26 U/l, p=0.010). A baseline MDA-LDL value of 110 U/l for differentiating between diabetics with and without ISR was defined as the cut-off value. Kaplan-Meier analysis demonstrated that a circulating MDA-LDL of ≥ 110 U/l correlated significantly with a higher prevalence of cardiac events than MDA-LDL <110 U/l (p=0.032)., Conclusions: Circulating MDA-LDL is a useful prognostic marker for future cardiac event in diabetic patients with CAD., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background: The interconnectivity of the peroxidation reaction system of myeloperoxidase (PRSM) or the reaction system of paraoxonase 1 (RSP1) with atherosclerosis remains elusive in patients with normal cholesterol levels., Methods: A total of 55 atherosclerotic patients with normal cholesterol concentrations and 45 control subjects were analyzed. Pearson's correlation was used to investigate the correlation between the levels of oxidative stress-related indices (HNE-LDL, MDA-LDL and protein carbonyls) and cholesterol indices (TC, HDL-C and LDL-C) and individual factor in RSP1 and PRSM (paraoxonase 1 activity, ionized calcium, myeloperoxidase peroxidation activity, or H2O2). Response surface regression (RSR) was used to analyze the interconnection of PRSM and RSP1 with the levels of oxidative stress-related indices and cholesterol indices., Results: The relation between PRSM and the increase of HNE-LDL and MDA-LDL was attributable to myeloperoxidase peroxidation activity, H2O2 concentrations and the interaction between myeloperoxidase peroxidation activity and H2O2 in the patients. PRSM preferred contribution to cholesterol levels in the cases. The interconnection of PRSM with TC was dependent on the association of PRSM with HDL-C and LDL-C., Conclusions: The shift of interconnection with HDL-C levels from RSP1 to PRSM represents a marker for atherosclerotic patients with normal cholesterol levels., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Background: Oxidative stress is associated with many diseases including cancer. Oral squamous cell carcinoma (OSCC) is a prevalent cancer involving oral cavity. We evaluate the activity of paraoxonase 1 (PON1) in serum samples of subjects suffering from OSCC along with malondialdehyde (MDA) levels, a marker for oxidative stress. Antioxidant status in OSCC may reflect the role of oxidative imbalance in the disease., Methods: Forty-five patients suffering with OSCC and 30 healthy controls were selected for the study. Serum paraoxonase (PON) and arylesterase (ARE) activities were measured in subjects suffering from OSCC and their healthy counterparts. To examine the status of lipid peroxidation, MDA concentrations were estimated and a correlation was determined between PON activities and MDA concentrations. MDA expression in cancer and normal adjacent tissue was studied through immunohistochemical (IHC) analysis. Total reactive oxygen species (ROS) level was determined in serum from normal and diseased subjects. Our results revealed that both PON and ARE activities of PON1 were significantly decreased in OSCC patients. Serum MDA concentrations were inversely correlated to PON activity. Immunohistochemical analysis showed a higher expression of MDA in cancerous tissue. Total ROS levels were found to be significantly elevated in cancer subjects., Conclusions: Along with other antioxidants, PON levels may act as an indicator of oxidative stress in cancer., (Copyright © 2013 Elsevier B.V. All rights reserved.)

Background: Despite the importance of oxidized LDL and small LDL particles as atherogenic lipoproteins, the relationship between oxidized LDL and the distributions of size subclasses of lipoproteins is not fully proved. We investigated the relationship of circulating malondialdehyde-modified (MDA)-LDL, an oxidized form of LDL, and lipoprotein subclasses in healthy men., Methods: The study group consisted of a total of 170 healthy Japanese men (55+/-9 y). Plasma cholesterol concentrations in major lipoproteins and their subclasses were determined by HPLC with gel permeation columns., Results: In univariate analysis, body mass index, waist circumference, blood pressure, white blood cell count, C-reactive protein, uric acid, fasting insulin, HOMA-IR, total cholesterol, triglycerides, each VLDL subclass cholesterol, each LDL subclass cholesterol, small HDL cholesterol, and very small HDL cholesterol were positively correlated with MDA-LDL, whereas adiponectin and large HDL cholesterol were inversely correlated with MDA-LDL. In stepwise multiple regression analysis, very small LDL cholesterol, medium VLDL cholesterol, very small HDL cholesterol, small HDL cholesterol, and systolic blood pressure were identified as independent determinants of MDA-LDL (R(2)=0.718, p<0.0001)., Conclusions: Circulating MDA-LDL concentrations are strongly associated with very small LDL cholesterol concentrations in healthy men. HDL size heterogeneity has a biphasic effect on MDA-LDL.

Background: We conducted a study to evaluate reactive oxygen species (ROS) and reactive nitrogen species (RNS) simultaneously together with the antioxidant status in patients with cervical carcinoma., Methods: We measured lipid peroxidation product, including malondialdehye (MDA), nitric oxide (NO) products, including nitrite (NO(2)(-)), nitrate (NO(3)(-)) and total nitrite (TNO(2)(-)) and antioxidant enzymes in 45 patients with cervical cancer and compared them against 30 healthy controls., Results: Plasma as well as erythrocyte MDA and plasma NO levels was higher (p<0.001) in cervical cancer as compared to healthy controls. Antioxidant enzymes, Superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities, were decreased (p<0.001) whereas glutathione S-transferase (GST) activity was increased (p<0.001) in cervical cancer patients. Lipid peroxidation and NO products accumulation correlated significantly with a deranged antioxidant system., Conclusions: We demonstrated a possible involvement of both oxidative and nitrosative stress, as evidenced by increased lipid peroxidation and NO levels with altered antioxidant defense system in the pathogenesis of cervical cancer.

Background: Collective evidences reveal that malondialdehyde (MDA), reduced glutathione (GSH) and ascorbic acid can modulate protein glycation. We investigated the concentrations of MDA, GSH, ascorbic acid and protein glycation in asthma patients to delineate the possible association among these parameters., Methods: Blood was collected from 18 asthma patients and 16 age and sex matched control subjects. Glycated hemoglobin (HbA1C), GSH, MDA, vitamin C, fructosamine and glucose were assessed in both groups. The effect of H2O2 on glycation of hemoglobin was studied by incubating normal healthy erythrocytes with either 5 or 50 mmol/l glucose concentration., Results: Plasma of asthma patients revealed significantly higher concentrations of lipid peroxides and fructosamine concentrations than the matched controls. Glycated hemoglobin concentrations were also found to be significantly increased. Ascorbic acid and GSH concentrations were decreased significantly in the test group when compared with the healthy control group. When the effects of fasting glucose, GSH and ascorbic acid on the concentrations of HbA1C and fructosamine were refuted by partial correlation analysis, MDA was found to be a significant determinant of HbA1c and fructosamine in patients with asthma. The in vitro model with human erythrocytes showed an enhancement of protein glycation by H2O2., Conclusion: An increased glycation of proteins was found in asthma patients. These data also support the premise that lipid peroxides per se do have a role to play in glycation of hemoglobin and plasma proteins.

Background: Reactive oxygen species (ROS), including superoxide anion radical (O2(-)), plays an important role in carcinogenesis. The human body has developed different antioxidant systems to defend against free radical attacks. We investigated the changes of the antioxidant status in the blood of patients with breast cancer., Methods: The O2(-) generation and the levels of malondialdehyde (MDA) were measured as an index of lipid peroxidation along with the examination of the activities of superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GRx), the levels of reduced glutathione (GSH), oxidized glutathione (GSSG), and vitamins A, C, and E., Results: The results showed that the levels of O2(-) and MDA, and the activities of antioxidant enzymes in the blood of the patients with breast cancer were significantly higher than the controls. However, the levels of vitamin C, GSH, GSSG and ratio of GSH/GSSG in the blood of the patients with breast cancer were significantly decreased compared to control subjects., Conclusions: Oxidative stress may be involved in breast cancer. The increased activities of erythrocyte antioxidant enzymes may be a compensatory upregulation in response to the increased oxidative stress.

Background: [corrected] Alcoholic liver diseases (ALD) are very common in lower socio-economical strata due to heavy drinking habits and multiple nutritional deficiencies. Ethanol causes liver damage by many mechanisms. The generation of lipid peroxidation by free radicals has been proposed as a mechanism for ethanol induced hepatotoxicity. These free radicals are destroyed by anti-oxidants. Many anti-oxidants are present in the diet, e.g., vitamin E, vitamin C etc. However, poor nutrition or malabsorption leads to deficiency of these vitamins. This may impair the anti-oxidative defense leading to ethanol induced oxidative stress and then to liver damage., Methods: Oxidative stress and antioxidant defense were assessed in patients with alcoholic liver disease. Serum malondialdehyde (MDA) concentrations were measured as an index of lipid peroxidation, i.e., oxidative stress; and serum vitamins E and C concentrations were measured as an index of antioxidant status., Results: Serum MDA concentrations were increased with the increase in severity of the disease. Concentrations of serum vitamins E and C were decreased in patients with alcoholic liver disease as compared to controls., Conclusions: Our observations may be due to increased demands of the same or increased utilization.

Background: Antioxidant consumption is claimed to be associated with improved antioxidant defenses and with the prevention of free radical-associated diseases. We evaluated if the regular supplementation with an antioxidant mixture modified oxidative stress parameters in healthy humans., Methods: Malondialdehyde (MDA), vitamin E (alpha-tocopherol), beta-carotene, and ubiquinol-10 were determined in plasma by HPLC; plasma 2-thiobarbituric acid reactive substances (TBARS) were evaluated fluorometrically. The supplement contained 106 IU vitamin E, 10 mg beta-carotene, 60 mg coenzyme Q-10, and 40 microg selenium., Results: After a 10-day wash out period, 16 healthy, free-living adults (31-48 years old; 9 women, 7 men) consumed the supplement daily during 30 days. At day 20, plasma concentration of vitamin E (alpha-tocopherol), beta-carotene, and ubiquinol-10 increased 45%, 66%, and 104%, respectively, over baseline values. Plasma MDA concentrations were reduced at days 20 (25%) and 30 (32%). Plasma TBARS concentrations decreased steadily during the treatment, reaching at day 30 an 11% decrease compared to baseline. Segregating by gender, both MDA and TBARS plasma concentrations were higher in men than in women at baseline. However, such differences disappeared after 30 days of supplementation., Conclusion: The observed modifications in variables associated with oxidative stress are indicative of an effective antioxidant action of the used mixture of lipid soluble compounds, and gender differences suggest that men should optimize their antioxidants defenses earlier in life than women.

Background: Dietary caloric restriction (CR) without malnutrition is effective in the control of diabetes mellitus by stabilizing glucose homeostasis and enhancing glycemic control. Mild and severe streptozotocin-induced diabetic and non-diabetic rats were subjected to caloric restriction and ad libitum feeding to evaluate their effects on oxidative stress and lipid profile in the plasma of experimental animals., Methods: Mild and severe diabetes were induced in Male Wistar rats by intraperitoneal injection of 35 and 65 mg/kg streptozotocin respectively. The experimental animals were subjected to 40% caloric restriction and ad libitum feeding for 9 weeks., Results: CR was effective in significantly reducing body weight, blood glucose, HbA IC and TG concentrations (all p < 0.001) in mild diabetic rats and non-significantly improving the plasma HDL-cholesterol concentrations. However, CR did not produce any significant effect on the antioxidant enzyme activities and MDA concentrations in all the groups nor in any of the parameters measured in non-diabetic rats except their overall weight change. There were significant (p < 0.001) decreases in body weight and non-significant fluctuating results in HbA IC and HDL-cholesterol in severe diabetic animals., Conclusions: These results demonstrate that caloric restriction is most effective in mild than in non-diabetic or severe diabetic animals.

Background: Oxidative stress is an important risk factor for the development and progression of several complications in hemodialysis patients. The aim of this study was to evaluate the effects of two different dialysis membranes on oxidative stress and selenium status., Methods: Forty long-term dialysis patients and 20 age-matched healthy controls were enrolled into our study. Serum malondialdehyde (MDA) and selenium (Se) concentrations, and glutathione peroxidase (GSH-Px) activities were determined before and after hemodialysis (HD) using a hemophan (H) or a polysulfone (PS) membrane., Results: MDA levels in the HD patients were significantly higher than those in the control group (p < 0.001). GSH-Px activity and selenium concentrations were significantly lower in HD patients compared to the control group (p < 0.001). MDA levels were significantly increased (p < 0.05); GSH-Px activity and selenium concentrations were significantly reduced (p < 0.001) in the PS membrane group compared to H membrane group after HD., Conclusions: Comparing with H membrane, PS membrane caused more oxidative stress and lower levels of Se in HD patients.

Background: The generation of reactive oxygen species (ROS) has been implicated in the pathogenesis of a vast array of disease processes including some neurological disorders., Method: Ten patients with Guillain-Barre syndrome (GBS) and 10 age and sex-matched controls were included in this study. The erythrocyte glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) levels, as well as plasma antioxidant vitamins C and E and serum glutathione-S-transferase (GST) levels were estimated spectrophotometrically., Results: The plasma vitamin E and the serum total glutathione-S-transferase levels were markedly increased in both pre- and post-treated cases of GBS when compared to controls. The erythrocyte glutathione and malondialdehyde levels were significantly reduced in GBS cases when compared to normals. However, plasma vitamin C and erythrocyte superoxide dismutase were not altered when compared to controls., Conclusion: Free radical toxicity may have an influence in patients suffering from GBS.

Background: A simple and reliable high-performance liquid chromatographic (HPLC) method has been developed and validated for the analysis of malondialdehyde (MDA) in human seminal plasma., Methods: After human seminal plasma is hydrolyzed, MDA is reacted with thiobarbituric acid (TBA) to form MDA(TBA)(2), a red-colored adduct with maximum absorbance at 532 nm. HPLC separation of the adduct in human seminal plasma was performed on a Lichrospher C(18) column., Results: A mobile phase composed of 0.025 mol/l KH(2)PO(4) (pH 6.2)--methanol in the ratio 58:42 (v/v) was found to be the most suitable for this separation. Under the chromatographic conditions described, the MDA-TBA adduct had a retention time of approximately 4 min and good separation and detectability of MDA in human seminal plasma sample was obtained. The method proved to be linear calibration in the range of MDA from 0.10 to 2.50 micromol/l. The relative standard deviations of within- and between-assay for MDA analysis were 3.1% and 3.8%, respectively. The average recovery was 90.0-98.8% for the human seminal plasma samples. The method has been successfully applied to the study of the lipid peroxidation levels in the seminal plasma of male infertility. Semen samples were obtained from healthy volunteers and infertile males. Ejaculates were classified into studied subgroups and defined as: obstructive azoospermia, non-obstructive azoospermia, oligozoospermia, asthenozoospermia, oligoasthenozoospermia and oligoasthenoteratozoospermia. With the exception of obstructive azoospermic group, MDA concentrations of seminal plasma in control group had very significant difference with those in other infertile groups (P < 0.01)., Conclusions: This indicated that lipid peroxidation could be harmful to male sperm and reproductive system, which may lead to male infertility.

Background/aim: Helicobacter pylori infection is associated with the development of atrophic gastritis and increased gastric epithelial proliferation that is important in developing gastric carcinoma. Some countries with a high prevalence of H. pylori infection have high gastric cancer rates, whereas in others these rates are low. Several theories have been advanced to explain this phenomenon. One of these explanations is that the concurrent parasitic infection that is common in the African population might alter the immune response to H. pylori infection and reduce the incidence of atrophic gastritis. The aim of the present study was to assess whether concurrent Schistosoma mansoni infection with H. pylori has an effect on gastric mucosal injury in view of cell proliferation, apoptosis, pathological changes, nitric oxide (NO), oxyradicals and antioxidant capacity status., Patients/methods: Between April 2001 and March 2002, 73 patients were subjected to upper gastrointestinal endoscopy for dyspepsia and liver cirrhosis in the National Liver Institute, Menoufiya University. Biopsies were obtained from any lesion as well as from apparently healthy mucosa. Specimens were preserved in RNA later solution, and then kept at -80 degrees C until utilized for estimation of DNA-flow cytometric assay, reduced glutathione (GSH), catalase (CAT), superoxide dismutase (SOD), NO and lipid peroxidation (LPO) product--malondialdehyde (MDA). Diagnosis of bilharziasis was done by stool analysis, or by sigmoidoscopy and rectal snip., Results: Of the 73 patients, 48 were H. pylori-positive, 34 of them were positive and 14 were negative for S. mansoni. Of the 25 H. pylori-negative cases, 18 were positive and 7 were negative for S. mansoni. Concurrent infection with S. mansoni occurred in 34 patients and they had reduced DNA S-phase (7.57 +/- 4.99 vs. 14.5 +/- 3.11, P = 0.001), reduced proliferation activity (9.95 +/- 3.95 vs. 16.78, P < 0.004) and reduced apoptosis (21.83 +/- 11.64 vs. 26.0 +/- 8.31, P > 0.05) compared with H. pylori infected patients alone., Conclusions: The results demonstrate that concurrent helminthes infection may modify the inflammatory response to gastric H. pylori infection manifested by the reduction of oxyradical-induced DNA-damage, apoptosis and cellular proliferation activity, and the increase in antioxidant production. Concurrent S. mansoni infection may have a protective effect against the possible progression of H. pylori-induced gastritis towards gastric carcinoma.

Background: Chronic exposure to cement dust has been reported to lead to several health problems. This study was designed to investigate the plasma oxidant and antioxidant status in cement plant workers and control subjects., Methods: Twenty-eight volunteer male cement plant workers and 30 volunteer office male workers (control) aged 29-54 years participated. The concentration of plasma vitamin C (P-VC), plasma vitamin E (P-VE), plasma malondialdehyde (P-MDA), and the activity of erythrocyte superoxide dismutase (E-SOD), plasma glutathione peroxidase (P-GSH-Px), and some serum biochemical parameters were measured in both groups., Results: The levels of MDA (175%), ALT (61%), and AST (39%) were significantly increased, while total RBC count (12%), Hb (11%) vitamin E (51%), C (35%), SOD (44%), and GSH-Px (51%) activities were markedly decreased, and the levels of urea, protein, and albumin triglyceride and cholesterol were almost the same in cement plant workers versus the control subjects., Conclusion: Cement workers are exposed to more oxidative stress compared to control subjects. To overcome these oxidative stresses, supplementation of antioxidant vitamins, such as alpha-tocopherol and ascorbic acid, may be beneficial. In addition, proper precaution to protect workers could prevent serious health problems.

Background: Patients with diabetes mellitus have been reported to show increased serum levels of modified low-density lipoprotein (LDL), including glycosylated, oxidized and small, dense LDL. This change has been suggested to represent an important risk factor for diabetic macroangiopathy. A common characteristic shared by these modified LDL species is the increase in electronegative charge on particle surfaces, which can be detected by agarose gel electrophoresis as "LDL charge modified frequency" (LDL-CMF) determined from the relative mobility of LDL fraction., Methods: LDL-CMF was measured in the sera from 129 outpatients with type 2 diabetes mellitus and compared with the data from 34 normal subjects., Results: The LDL fraction from diabetics migrates more closely to the anode side as compared with that from normal subjects. The LDL-CMF measured in diabetics, 5.5+/-8.1%, was significantly (p<0.0001) higher than 0.6+/-3.4% in normal subjects. Serum LDL-CMF showed significant positive correlations with triglyceride at r=0.552 (p<0.0001) and malondialdehyde modified LDL at r=0.390 (p<0.0001), as well as systolic blood pressure, body mass index, fasting plasma glucose, hemoglobin A(1c), total cholesterol, free fatty acid (FFA) and homeostasis model assessment ratio. It showed negative correlations with high-density lipoprotein and total superoxide dismutase activity., Conclusion: The results indicate that LDL-CMF reflects the degree of serum LDL modification in diabetics and can be regarded as an important risk factor for diabetic macroangiopathy.

Background: Isoprostanes are prostaglandin-like end products of arachidonic acid peroxidation that are produced by a free radical-catalyzed mechanism. Considering its free radical-dependent formation and potent contractor effect, it is postulated that isoprostane 8-iso PGF2alpha may play an important role in oxidative stress-related smooth muscle dysfunction. These substances may also influence bladder activity directly by effects on the smooth muscle. The present study was designed to measure traditional biochemical parameters (MDA, TAS, vitamin E) in plasma and 8-iso PGF2alpha concentrations in urine of patients with spinal cord injury and to evaluate the relation of urinary isoprostane concentrations to the bladder function., Methods: All spinal cord patients underwent urodynamic evaluations. The biochemical tests were performed in both hyperreflexic bladder group (n = 23) and areflexic bladder group (n = 10), and the findings were compared to those of the patients with normally functioning bladder (controls, n = 19)., Results: Urine 8-iso PGF2alpha concentrations were significantly increased in hyperreflexic group (median value 0.89 pg/mg creatinine) compared to both control (0.52 pg/mg creatinine) and areflexic groups (p < 0.001). The lowest concentrations of urinary 8-iso PGF2alpha were observed in the areflexic group (0.22 pg/mg creatinine), and these were positively correlated to the plasma MDA concentrations in areflexic patients (p = 0.05; r = 0.684)., Conclusion: Isoprostanes may be involved in the pathogenesis of neurogenic bladder dysfunction. It may be of value to determine the urinary concentrations of 8-iso PGF2alpha in order to distinguish areflexic bladders from the hyperreflectics.

Background: Oxygen free radicals have been implicated as mediators of tissue damage in patients of rheumatoid arthritis (RA). This study was designed to elucidate plasma oxidant/antioxidant status in rheumatoid arthritis, with the aim of evaluating the importance of antioxidant therapy in the management of this disease., Methods: The study included 40 patients of rheumatoid arthritis who were randomly divided into two subgroups of 20 each. One group received conventional treatment for 12 weeks and in the other group conventional treatment was supplemented with antioxidants for the same duration. Twenty age- and sex-matched normal individuals constituted the control group. Blood samples of controls and patients were collected at the time of presentation and analyzed for total thiols, glutathione, vitamin C and malondialdehyde (MDA-marker of oxidative stress). The investigations were repeated in the patients after 12 weeks., Results: The blood concentrations of total thiols, glutathione and vitamin C were found to be significantly lower in rheumatoid arthritis patients as compared to healthy controls, while the concentrations of MDA were much higher. There was a statistically significant increase in the posttreatment concentrations of these antioxidants, along with a decrease in the concentrations of MDA., Conclusions: The antioxidant defense system is compromised in rheumatoid arthritis patients. There is a shift in the oxidant/antioxidant balance in favor of lipid peroxidation, which could lead to the tissue damage observed in the disease. The results suggest the necessity for therapeutic co-administration of antioxidants along with conventional drugs to such patients. However, due to the limited number of cases included in this study, more studies may be required to substantiate the results and arrive at a definite conclusion, in terms of safety and efficacy of adding on antioxidant therapy for the treatment of RA.

Background: Chronic lymphocytic leukemia (CLL) is a rare neoplasm that comprises a substantial proportion of all leukemias in middle-aged persons and is the most common type among elderly persons. The major causes are not known nor is there a detailed understanding about how the elusive origin(s) may relate to clinical expression, basic biological mechanisms, or pathogenesis., Methods: Glutathione peroxidase (GSH-Px), glutathione reductase (GRD), Cu-Zn superoxide dismutase (Cu-Zn SOD) activities, glutathione (GSH), nitric oxide (NO(*), and malondialdehyde (MDA) concentrations were measured in serum of patients with CLL and a healthy control group., Results: Serum GSH-Px, Cu-Zn SOD activities, GSH concentration were lower in patients with CLL while serum NO(*) and MDA concentrations were higher in these patients compared with the control group. Serum GRD activity was not statistically significant in patients with CLL compared with the control. However, there was no statistically significant difference in the parameters on the basis of stages in these patients. Serum GSH concentration negatively correlated with serum MDA (r=30.63, p<0.05) and NO(*) concentrations (r=0.72, p<0.05) in patients with advanced stage (III+IV). However, no other correlation could be found among the parameters in healthy controls and patients with CLL CONCLUSIONS: There is significant changes in antioxidant defense system in CLL cases, which may lead to enhanced action of oxygen radical, resulting in lipid peroxidation.

Background: Malondialdehyde (MDA), ascorbic acid and reduced glutathione (GSH) have been reported to play a possible role in glycation of proteins. This study was performed to evaluate this correlation in nephrotic syndrome patients by comparing the levels of fructosamine with MDA, ascorbic acid and GSH., Methods: Fifteen children with nephrotic syndrome during relapse and 10 age- and sex-matched healthy controls were enrolled for this study. Whole blood GSH, plasma MDA, total ascorbic acid and fasting glucose were analyzed in both the groups. Partial correlation analysis was performed to predict the independent association of MDA, ascorbic acid and GSH on fructosamine., Results: Plasma MDA and fructosamine levels were found to be increased in nephrotic syndrome patients when compared with controls. Plasma ascorbic acid and whole blood GSH were decreased in nephrotic group vs. healthy controls. Partial correlation analysis showed a significant positive correlation between fructosamine and MDA., Conclusions: Present data point to a possible involvement of MDA in the glycation of protein in non-diabetic nephrotic syndrome patients, and provide support for the potential use of an antioxidant therapy in these patients.

Background: We wanted to investigate the effect of X-rays on mononuclear blood cells (MNCs) and red blood cells (RBCs) of radiology technicians exposed to X-rays in hospital., Methods: DNA damage was detected by fluorometric analysis of DNA unwinding. Glutathione levels were measured with enzymatic method in mononuclear blood cells. Glutathione content and catalase (CAT) activity of erythrocytes, and plasma malondialdehyde (MDA) levels were determined by spectrophometric methods., Results: An insignificant increase in plasma malondialdehyde levels and a significant decrease in mononuclear blood cells glutathione levels were observed in nonsmoking radiology technicians. In smoking radiology technicians, on the other hand, in addition to an increase in plasma malondialdehyde levels, DNA damage was also significantly apparent. Besides mononuclear blood cells' glutathione depletion, the glutathione content of red blood cells was also found to be decreased., Conclusion: It can be suggested that smoking seems to augment the toxic effects of radiation.

Background: Urinary hydrogen peroxide was postulated to be a biomarker of oxidative stress. We estimated urinary hydrogen peroxide along with other established parameters of oxidative stress in malignancies where oxidative stress is well documented., Methods: The oxidative stress markers tested were concentrations of erythrocyte glutathione, erythrocyte malonaldehyde (MDA) and plasma hydroperoxide, and activities of plasma glutathione-S-transferase (GST) and erythrocyte catalase. Urinary hydrogen peroxide was measured by a modified ferrous ion oxidation xylenol orange version-2 (FOX-2) method on a spot random sample of urine., Results: In healthy controls (n=10), erythrocyte glutathione concentration was 4.41+/-0.057mg/g of hemoglobin, plasma hydroperoxide was 2.5+/-0.07 micromol/l, erythrocyte MDA was 0.9+/-0.15 nmol/ml of packed cell suspension and erythrocyte catalase and plasma GST were 74.66+/-9.2/s/ml of packed cell suspension and 6.12+/-0.84 IU/l, respectively. In cancer patients (n=25), erythrocyte glutathione, plasma hydroperoxide and erythrocyte MDA were 9.32+/-0.42 mg/g of hemoglobin, 6.2+/-0.13 micromol/l and 2.3+/-0.27 nmol/ml of packed cell suspension, respectively; and activities of erythrocyte catalase and plasma GST were 151.04+/-6.5/s/ml of packed cell suspension and 10.9+/-0.36 IU/l, respectively. Urinary hydrogen peroxide concentration was 15+/-9.8 micromol/l in the healthy controls and 56.3+/-3.9 micromol/l in cancer patients., Conclusion: Urinary hydrogen peroxide may be a marker of oxidative stress in malignancies.

Background: The cardiovascular protective mixture (CVPM) is a concoction of nine Chinese traditional medicines: Dan-shen root, Szechwan lovge rhizome, Chinese angelica, Hawthorn fruit, Safflower, Peach seed, Red peony root, earthworm, and membranous milkvetch root. These medicines are used to cure cardiovascular disease in China., Methods: Animal models were established by feeding the Sprague-Dawley (SD) rats with lipid-rich forage. Serum total cholesterol (TC) and low-density lipoprotein cholesterol (LDL-C) were measured. Malondialdehyde (MDA) content was determined to monitor lipid peroxidation. The 6-keto-prostaglandin F(1alpha)(6-keto-PGF(1alpha)) concentration was measured by radioimmunoassay to investigate the content of prostacyclin (PGI(2)). Electron microscope (JEM-1200EX) was used to observe the microstructure of the vascular endothelium. Rat aortic endothelial cell was cultured to investigate the effect of CVPM on vascular endothelial cell in vitro., Results: CVPM inhibited the accumulation of TC, LDL-C, and MDA in vivo, when the rats were fed with cholesterol diet. CVPM promoted synthesizing and excreting of PGI(2), since it is capable of activating the proliferation of vascular endothelium in vitro. Electron micrographs showed that CVPM had notable protective effect on the vascular endothelium and prevented the shedding of these cells from subendothelial layer., Conclusions: CVPM could ameliorate the internal environment in which vascular endothelial cells lived, and activate the proliferation of these cells. Through these mechanisms, CVPM protect vascular endothelial cell from being harmed by excess cholesterol in vivo.

Background: We previously showed that apricot sulfurization workers (ASW) are exposed to high concentrations of SO(2), resulting in an asthma-like syndrome. The aim of this study was to evaluate whether oxidative stress plays a role in the pathogenesis of asthma-like syndrome due to the high concentrations of SO(2) exposure in agricultural environment., Methods: Serum antioxidant enzyme activities and malondialdehyde (MDA) concentrations, which are markers of lipid peroxidation, and pulmonary function tests (PFT) were measured in 40 volunteer ASW and compared to 20 healthy control subjects., Results: The superoxide dismutase (SOD, 2.2+/-0.6 vs. 3.2+/-0.7 U/ml), glutathione peroxidase (GSH-Px, 0.6+/-0.3 vs. 1.1+/-0.3 U/ml) and catalase (107.6+/-27.4 vs. 152.6+/-14.3 k/l) activities in ASW were significantly (p<0.0001) lower than controls, whereas the malondialdehyde concentration (4.1+/-0.9 vs. 1.9+/-5.3 nmol/l) was higher in ASW (p<0.0001). ASW had significant decreases in pulmonary function parameters after exposure., Conclusion: These results show that occupational exposure to high concentrations of SO(2) enhances oxidative stress and lipid peroxidation may be considered as a new mechanism of SO(2)-induced bronchoconstriction.

Background: Alpha-tocopherol and ascorbic acid form a part of scavenger system influencing the level of oxidative stress in diabetes mellitus. The aim of this study was to evaluate serum concentrations of alpha-tocopherol and ascorbic acid in Type 1 and Type 2 diabetes mellitus and to compare them with the presence of vascular complications as well as with oxidative stress and endothelial dysfunction., Methods: A total of 38 Type 1 and 62 Type 2 diabetic patients were subdivided into those with and without angiopathy. Serum alpha-tocopherol and ascorbic acid concentrations were estimated in all patients and in 38 healthy persons. Their results were compared with diabetes control, with oxidative stress measured by plasma malondialdehyde and with endothelial dysfunction estimated by serum N-acetyl-beta-glucosaminidase activity. In addition, the differences in biochemical variables were compared between patients with and without angiopathy., Results: Serum alpha-tocopherol related to the sum of cholesterol and triglyceride concentrations (AT/CHT ratio) was significantly lower in diabetic patients with macroangiopathy than in those without vascular changes (p<0.05). Serum ascorbic acid levels were significantly lower only in Type 2 diabetic patients with macroangiopathy as compared with healthy controls as well as with patients without vascular disease (p<0.01). Positive relationship was observed between serum alpha-tocopherol and cholesterol or triglyceride concentrations in both Type 1 and Type 2 diabetic patients. The presence of oxidative stress together with endothelial dysfunction measured by N-acetyl-beta-glucosaminidase activity was accompanied by lower AT/CHT ratio (p<0.005) in Type 2 diabetic patients., Conclusion: Diabetic patients with proven angiopathy or with advanced oxidative stress and endothelial dysfunction have significantly lower AT/CHT ratio and ascorbic acid concentration in serum. Their low concentrations may participate at the increased level of oxidative stress in these individuals.

Background: Serum and tissue concentrations of tumor markers or some metabolites are considered to be helpful in diagnosis and follow-up of the central nervous system (CNS) disease. However, markers currently available are not sufficiently sensitive and specific to be used as actual diagnostic tools. Differentiation between the malignant and benign lesions of the CNS is very important, both for determining the optimum therapeutic approach and to predict morbidity and mortality of the disease. Accurate diagnosis of a malignant disease is mostly performed through a surgical resection and histopathologic evaluation. Free oxygen radicals (FOR) are thought to take part in oncogenesis and cellular differentiation. We explored whether FORs can be used as diagnostic tumor markers., Methods: We investigated the concentration of malondialdehyde (MDA) in the serum and tumor tissue of patients with glial tumor. We have studied 30 patients with malign glial tumor (grades III and IV astrocytoma), 30 patients with low grade glial tumor, 28 healthy individuals, and 10 patients with nontumorous lesions (lobectomy for epilepsy)., Results: Patients with CNS tumors showed higher serum MDA concentration compared to control groups (epilepsy patients and healthy subjects). These patients had a higher tumor tissue MDA concentration compared to lobectomy tissue from epilepsy patients. Serum and tissue MDA concentrations were also higher in the malignant glial tumor group compared to the low grade glial tumor group., Conclusions: Although not specific, tissue and serum concentrations of FORs can be used as a marker to detect the presence and grade of CNS tumors. Further studies are needed to determine the optimum cutoff value for use of serum and tissue MDA concentrations in brain tumors.

Background: Nephrotic syndrome (NS) is a stressful condition for children where oxidative damage would also influence the response of these patients to therapy., Methods: The present study was conducted in children with nephrotic syndrome during relapse and remission and in 10 age- and sex-matched healthy volunteers. Red cell glutathione (GSH), superoxide dismutase (SOD) and malondialdehyde (MDA) concentrations as well as plasma ceruloplasmin (CP) and vitamin E concentrations were analyzed in controls and in patients., Results: Erythrocyte superoxide dismutase concentrations were significantly increased in both the groups when compared to controls. Erythrocyte glutathione significantly decreased in nephrotic syndrome in remission along with plasma vitamin E concentrations in both the groups. A significant increase in plasma ceruloplasmin was observed in cases in remission. However, no significant change was observed in the concentrations of erythrocyte malondialdehyde., Conclusion: Thus, antioxidant concentrations change considerably, indicating a compensatory mechanism to cope up with increased pro-oxidant status in such cases., (Copyright 2002 Elsevier Science B.V.)

Background: Oxidative stress is currently suggested as a mechanism underlying diabetes. The present study was designed to evaluate isoprostane levels in plasma and in urine in type 2 diabetic patients, and to compare them to other currently used biomarkers of oxidative stress., Methods: The work was performed in a control group (n = 10) and in a type 2 diabetic group (n = 10). Besides the traditional biochemical parameters, we evaluated the plasma and urine levels of isoprostanes and malondialdehyde (MDA) as markers of oxidative stress., Results: We found increased plasma and urine MDA in the diabetic patients and almost significantly decreased plasma vitamin E. Urinary isoprostane levels in diabetic patients were increased but they presented a strong tendency to a decrease in plasma isoprostanes. It is therefore suggested that, in the studied diabetic patients, although the production of isoprostanes in the body was increased (as other plasma oxidative stress biomarkers were altered) it did not lead to an increase in plasma isoprostane levels. It could be hypothesised that this results from an increased elimination of this metabolite and therefore an increased excretion in urine., Conclusion: Our results showed that the measurement of same oxidative stress biomarker, isoprostane, in two different biologic fluids, plasma and urine, led to divergent results and emphasised the importance to measure a biomarker both in the circulation fluid (plasma) and in the elimination fluid (urine), to have a general idea of what is occurring in the organism., (Copyright 2002 Elsevier Science B.V.)

Background: Free radical-mediated changes are thought to be involved with atherosclerosis in patients with chronic renal failure., Methods: The protein carbonyl and malondialdehyde (MDA) levels in serum as the markers of radical-induced protein and lipid oxidations were measured in chronic renal failure patients., Results: Serum carbonyl and MDA levels in both hemodialysis and peritoneal dialysis patients were not found to be different as compared with healthy subjects. In both patient groups, the approximately twofold increment in total antioxidant activity (ferric reducing/antioxidant power; FRAP) and uric acid values in serum were found. The high uric acid levels in both patient groups might be partly responsible for the increment in FRAP values. In addition, all patients received multivitamin preparations including ascorbate, which was also a major antioxidant in serum., Conclusions: Our data suggest that oxidative stress does not become the major threat for patients with chronic renal failure. The increment in endogenous and exogenous antioxidant capacities in serum might be thought to prevent any possible radical-induced damage in patients with chronic renal failure. In addition, the increased nitric oxide (NO) levels especially in hemodialysis patients might likely favor an antioxidant effect., (Copyright 2002 Elsevier Science B.V.)

Background: Preeclampsia is characterized by endothelial cell dysfunction, and lipid peroxidation and alterations of immune responses may be involved in the pathogenesis of this disease. The aim of the present study was to examine changes in plasma malondialdehyde (MDA) level, an indicator of lipid peroxidation, and adenosine deaminase (ADA) activity, as a marker of T-cell activation in preeclampsia, and evaluated the possible relationship between those parameters in the pathogenesis of preeclampsia., Methods: Plasma levels of MDA, an end product of lipid peroxidation induced by reactive oxygen species, and ADA activities were measured in 26 women with preeclampsia and 26 normal pregnancies., Results: In preeclampsia, plasma MDA level and ADA activity averaged 0.43 +/- 0.03 micromol/l and 15.8 +/- 0.8 U/l, respectively, which were significantly higher than those of normal pregnancy (0.31 +/- 0.02 micromol/l and 9.5 +/ -0.6 U/l, respectively) (P<0.05). In addition, plasma MDA level was positively correlated to ADA activity in preeclampsia (r=0.52, P<0.05)., Conclusions: These results suggest that enhanced lipid peroxidation and T-cell activation, and the presence of possible interrelationship and cross talk between those parameters may be related at least partly to the pathogenesis of preeclampsia., (Copyright 2002 Elsevier Science B.V.)

Background: Free oxygen radicals have been proposed as important causative agents of aging. We have evaluated age-related changes in antioxidant enzyme activities and lipid peroxidation., Methods: We measured erythrocyte superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and plasma malondialdehyde (MDA) levels. One hundred and seventy six healthy subjects were divided into five groups: Group 1 (n = 25; 0.2-1 year-old), Group 2 (n = 28; 2-11 years), Group 3 (n = 23: 12-24 years), Group 4 (n = 40; 25-40 years), Group 5 (n = 60: 41-69 years)., Results: SOD activities in Group 5 were significantly lower than in the other groups (P < 0.001). GPx and CAT activities and MDA levels in Group 5 were significantly higher than the other groups (P < 0.001, respectively). CAT activity in Group 4 was significantly higher than group 1 and group 2 (respectively, P < 0.001), and in group 3 was high compared to Group 2 (P < 0.001). There were negative correlations between SOD activities and age (P < 0.001). Conversely, there were positive correlations between CAT, GPx and MDA levels and age (P < 0.001). CAT activities of women in Group 2 were found to be high compared to the men (P < 0.05). MDA levels of women in Group 5 were higher than in the male groups (P < 0.001)., Conclusions: We found age-related differences in erythrocyte antioxidant enzyme activities. Furthermore, peroxidative injury is raised in the aging process.

We studied changes in lipid peroxidation, vitamin E status and lipid profile due to smoking in healthy subjects, patients with acute myocardial infarction (MI), and in stabilized patients surviving MI. A significant increase in malondialdehyde (MDA) concentrations was observed in MI patients, more than in smokers (P<0.05), as compared to control. The plasma vitamin E as well as the ratio of vitamin E/lipids were significantly lower in MI patients as compared to stable ischemic heart disease (IHD) patients and controls. Our data show that smoking is associated with lowered antioxidant status in MI.

Oxygen free radicals are important mediators of both physiological and pathological events. In acute lung injury, the activated lymphocytes stimulate tumor necrosis factor (TNF) and other cytokines. These lymphokines augment free radical generation by polymorphonuclear leukocytes (PMNLs), macrophages and other cells which may ultimately produce acute respiratory distress syndrome (ARDS). This is supported by our results presented here in that there is a significant increase in lipid peroxidation products in patients with established ARDS. The amount of lipid peroxidation was significantly higher in the established ARDS group compared to patients who are at risk for ARDS. Nitric oxide concentrations were significantly decreased in established ARDS compared to the control and those who are at risk for ARDS. Fatty acid analysis of the plasma phospholipid fraction revealed a significant decreased in linoleic acid, gamma-linolenic acid, dihomo-gamma-linolenic acid and arachidonic acid levels of n-6 series and alpha-linolenic acid, eicosapentaenoic acid, docosa-hexanenoic acid of n-3 series. Patients who are at risk for ARDS have decreased levels of gamma-linolenic acid of the n-6 series, alpha-linolenic acid and eicosapentaenoic acid of the n-3 series. These results suggest that lipid peroxides and alteration in essential fatty acid metabolism may have a role in the pathogenesis of ARDS.

The aim of this research was to determine levels in blood of vitamin E, beta carotene, lipid peroxidation as malondialdehyde (MDA), reduced glutathione (GSH) and glutathione peroxidase (GSH-Px) activity in patients with psoriasis. Studies were carried out on 34 patients with moderate and severe psoriases and healthy age-matched controls. Red blood cell (RBC) and plasma samples from healthy and patient subjects were taken. Levels of GSH and the activity of GSH-Px in both plasma and RBC samples were significantly (P<0.001) lower in patients with psoriasis than in controls, whereas beta carotene levels in plasma and MDA levels in RBC samples were significantly (P<0.01, P<0.001) higher in patients with psoriasis than in controls. However, vitamin E and MDA levels in plasma did not differ statistically. Although being far from conclusive, these results provide some evidence for a potential role of increased lipid peroxidation and decreased antioxidants in psoriasis.

Extracorporeal elimination of low density lipoprotein (LDL) is frequently used in drug-resistant hypercholesterolemia. LDL-immunoapheresis selectively removes LDL and lipoprotein(a) [Lp(a)] from plasma. Lipid peroxidation is one unwanted side effect, that occurs during extracorporeal plasma treatment. The purpose of this study was to investigate the effect of LDL immunoapheresis on lipid peroxidation. Before and after a single LDL-immunoapheresis treatment, plasma concentrations of lipid hydroperoxides, determined with two different spectophotometric assays, thiobarbituric acid-reacting substances (TBARS), determined spectrophotometrically and malondialdehyde (MDA), determined by an MDA-TBA/HPLC method, were measured in 13 hypercholesterolemic patients. In addition MDA was also determined in the eluate of the apheresis column. Before treatment, plasma cholesterol and LDL cholesterol concentrations were significantly higher in patients than in healthy control subjects, as were the lipid peroxidation products. LDL-immunoapheresis treatment of the patients led to significant decreases in total cholesterol (69+/-8%), LDL-cholesterol (79+/-7%), HDL-cholesterol (35+/-17%), triglycerides (38+/-21%), apolipoprotein-B (77+/-6%), apolipoprotein-A1 (25+/-5%) and Lp(a) concentrations (76+/-10%). Changes in plasma lipid peroxide concentrations (17+/-8 nmol/l before vs. 14+/-5 nmol/l after treatment) were not significant, neither were those in TBARS (3. 0+/-2.6 micromol/l vs. 2.3+/-1.3 micromol/l) or MDA concentrations (1.03+/-0.17 micromol/l vs. 1.0+/-0.20 micromol/l). Patients with high baseline values showed a decrease, whereas others did not. MDA was present (0.57+/-0.13 micromol/l) in the eluate of the apheresis column, suggesting that, along with LDL, lipid peroxidation products are also removed. From these results we conclude that a single LDL-immunoapheresis treatment effectively reduces LDL and Lp(a) in the absence of increases in plasma lipid peroxidation products.

Serum N-acetyl-beta-glucosaminidase activity was evaluated in 40 Type 1 and 40 Type 2 diabetic patients and compared with parameters of diabetes control and oxidative stress. Significantly increased mean serum N-acetyl-beta-glucosaminidase activity was found in both groups of diabetic patients as compared with the corresponding group of healthy persons (p < 0.01). Oxidative stress measured by plasma malondialdehyde concentration was significantly higher in Type 2 than in Type 1 diabetic patients (p < 0.01) but in comparison with control subjects it was higher only in Type 2 diabetes. Plasma malondialdehyde concentration positively correlated with body mass index (r=0.77, p<0.001) and with serum N-acetyl-beta-glucosaminidase activities (r=0.57, p <0.001). Treatment of 10 Type 2 diabetic patients with antioxidant alpha-tocopherol caused a significant decrease in malondialdehyde concentration (p < 0.001) which was accompanied by a decrease of N-acetyl-beta-glucosaminidase activity (p < 0.01). We conclude that serum N-acetyl-beta-glucosaminidase activity may be influenced by oxidative stress which is more pronounced in Type 2 than in Type 1 diabetic patients.

High resolution B-mode ultrasonography of the carotid arteries has been used to investigate the signs of early atherosclerotic vessel wall disease by measuring the intima-media thickness (IMT). We examined the association between IMT and lipid peroxidation and found IMT to be increased in a group of patients with respect to controls (1.430+/-0.341 mm versus 0.703+/-0.201 mm, P < 0.001). Plasma and erythrocyte malondialdehyde (MDA) levels were also significantly higher (P<0.001) and the erythrocyte reduced glutathione (GSH) levels were significantly lower (P <0.001) in the patients with respect to the controls. In the groups of patients there was no significant correlation between the mean IMT and the plasma and erythrocyte MDA levels or the erythrocyte GSH levels. In conclusion determination of lipid peroxides would be especially important and advisable in patients with increased carotid IMT. Type II diabetes and hypertension were also associated with increased IMT.

The aim of the present work was to investigate the biological hazard of photooxidation products of m-chloroperbenzoic acid (mCPBA), as a novel photo-sensitizer, on lysis and membrane lipid peroxidation of human red blood cells (RBC). The photohemolysis activity of mCPBA oxidative products was concentration- and exposure time-dependent. Ten minutes photoexposure time and 100 micromol/L of mCPBA concentration were optimum to study the effect of generated superoxide (O2.-) and hydroxyl (.OH) radicals on RBC. The hemolytic effect of mCPBA was highly significantly inhibited by formate (as an .OH radical scavenger) compared with the partial inhibition effect of SOD-like Cu(II) complex (as O2.- radical Scavenger). The MDA value (an end product of membrane lipid peroxidation of RBC) induced by mCPBA was highly significantly decreased by formate. The generation of O2.- radicals by mCPBA was also confirmed by the partial hemolytic effect of phenazine methosulfate (PMS., O2.- radical generation). The data suggest the molecular mechanism of the oxygen radical species (O2.- and .OH through the photosensitization reaction of mCPBA and explain that hydroxyl radicals (.OH) play an active role in the photohemolysis process and peroxidation of membrane lipids of human erythrocytes.

Liver ischemia followed by reperfusion is an important and common clinical event associated with the activation of an endogenous inflammatory response. The aim of this study was to determine the effects of cyclosporin A (CsA) and ibuprofen (IBU) on ischemia-reperfusion injury. Male Spraque-Dawley rats were subjected to 60 min of total liver ischemia followed by 120 min reperfusion. Liver tissue samples were obtained for measurements of malondialdehyde (MDA) levels as an index of tissue lipid peroxidation by thiobarbituric acid assay. Three groups of animals were pre-treated with CsA or IBU or both. Treatment with these agents was given at onset reperfusion after ischemia. The other groups were designated as ischemic controls, non-ischemic controls and reperfusion group without treatment. Ischemic control animals showed increased liver MDA levels and in the reperfusion group MDA levels were significantly higher than ischemic levels. CsA and IBU-treated animals had better survival and diminished liver MDA levels. The most significant decrease MDA levels was observed in the group treated with two agents which were given together. Serum enzyme levels were significantly higher in the reperfusion group than in the ischemic controls and the enzyme levels were significantly diminished after the treatments. This study suggests that CsA and IBU may be important agents in modulating lipid peroxidation in ischemia-reperfusion liver injury, and combined therapy with these agents may be more effective in treatment of ischemia-reperfusion injury.

Sixty-six postmenopausal women were randomly divided into three groups. The first group (n = 22) received transdermal oestradiol (0.05 g/day) for six months. Transdermal oestradiol was given during three weeks but was not given in the following week of each month during six months. In addition to the first group's therapy, medroxyprogesterone acetate (MPA; 10 mg/day, per orally) was administered to the second group (n = 22) for the last ten days. Vitamin E (600 mg/day, per orally) was given to the third group (n = 22) in addition to the first and second group therapy every day during six months. Total cholesterol, high density lipoprotein (HDL), very low density lipoprotein (VLDL) and low density lipoprotein (LDL) cholesterol, malondialdehyde (MDA), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) levels of the three groups were measured at the beginning and at the end of therapy. In the transdermal oestradiol and transdermal oestradiol + MPA groups, post-treatment serum total, VLDL and LDL cholesterol levels decreased (P < 0.05) whereas HDL cholesterol level increased (P < 0.05). No significant difference was found in the levels of MDA, SOD and GSH-Px. In the third group, pre-treatment levels of total (P < 0.05), VLDL (P < 0.05), LDL cholesterol (P < 0.01) and MDA (P < 0.05) were high compared to post-treatment. Inversely, HDL cholesterol (P < 0.05) and vitamin E (P < 0.01) levels increased after the treatment. However, there was no significant difference in the levels of SOD and GSH-Px. In conclusion, in the post-menopausal period, because of the positive changes after hormone replacement plus vitamin E therapy, we suggest that hormone replacement and vitamin E combined therapy is effective in prevention of cardiovascular diseases.

There is controversy as to the clinical importance of providing haemodialysis (HD) with biocompatible versus non-biocompatible membranes. The effects of both acute and chronic dialysis with a biocompatible membrane (polyacrylonitrile, PAN) and a non-biocompatible membrane (cuprophane, CU) on the structural and functional properties of human erythrocytes have been examined. All 27 studied HD patients had increased erythrocyte osmotic fragility (OF) compared to controls; a single CU HD decreased mean OF (% lysis) by 13% without altering cell cholesterol. A single PAN HD decreased OF by a significantly greater amount (24%) and was associated with a 20% reduction in cell cholesterol. Chronic PAN HD for 6 months was associated with a sustained reduction in osmotic fragility compared to chronic CU HD (mean lysis 16% vs 45%) with no differences in mean pre-HD cell cholesterol. A single CU HD was associated with increased mean erythrocyte malonyldialdehyde (MDA) and reduced membrane content of spectrin and band 3 and this was significantly different from the effects of PAN. A single CU or PAN HD had no significant action on reduced glutathione (GSH), ankyrin, actin or sodium pump activity. Chronic HD was associated with increased GSH, and decreased ankyrin and band 3 protein compared with controls but the results for CU and PAN were not different. There was a non-significant tendency for higher MDA levels after chronic CU HD compared to PAN. These results indicate that the structural integrity of erythrocytes is improved by PAN HD with respect to CU but this difference cannot easily be ascribed to gross changes in structural proteins, ionic homeostasis or oxidation status.

Effects of aging and hypercholesterolemic diet on lipid peroxidation and antioxidant status were investigated in rats. The rats were divided into four groups of ten: Group I; young rats receiving standard lab chow; Group II; young rats on hypercholesterolemic diet (0.4 g/rat/day); Group III; aged rates receiving standard lab chow; Group IV; aged rats on hypercholesterolemic diet (0.4 g/rat/day). Plasma lipid peroxidation end product level was determined as thiobarbutiric acid reactive substances (TBARS). Plasma cholesterol concentration was analyzed by a kinetic enzymatic method. Erythrocyte superoxide dismutase (CuZn SOD), glutathione peroxidase (GSH Px) and glutathione (GSH) levels were determined spectrophotometrically. Cholesterol values were found to be significantly high (p < 0.001), TBARS (0.05 > p > 0.02) and GSH (p < 0.001) levels significantly low in aged rats in comparison with young rats. Hypercholesterolemic diet induced significant increases in GSH (p < 0.001) and CuZn SOD (p < 0.001) levels, whereas a significant decrease in GSH Px activity (0.05 > p > 0.02) was observed in aged rats. In young rats hypercholesterolemic diet caused a significant increase in both GSH and CuZnSOD levels. Our results indicate an imbalance between radical production and destruction in favour of prooxidant conditions in the young rats and the induction by hypercholesterolemic diet of the antioxidative response in erythrocytes.

The measurement of malondialdehyde (MDA) in biological fluids remains a popular method for the quantification of free radical damage to lipids in vivo. Several diseases of prematurity are thought to be related to oxidative injury and previous studies have found elevated MDA in plasma and urine in preterm infants. Our aim was to investigate the relationship between plasma and urinary MDA levels in preterm infants during the first week of life using a high-performance liquid chromatography (HPLC) based, thiobarbituric acid (TBA) assay with paired plasma and urine samples. We obtained 50 paired samples, and were unable to demonstrate a relationship between the two parameters after the first day of life. In 18 cases a further urine sample was collected 24 h later. There was a positive correlation (r = 0.54, P = 0.02) between plasma MDA and urinary MDA 24 h later. The finding that plasma changes in MDA are reflected in urine 24 h later validates the use of urinary MDA as a marker of whole body lipid peroxidation in populations without renal disease.