Low density lipoprotein immunoapheresis does not increase plasma lipid peroxidation products in vivo.

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.     

Elevated plasma homocysteine concentrations in severe preeclampsia and eclampsia

Homocysteine is an essential amino acid required for the growth of cells and tissues in the human body. Maternal hyperhomocysteinemia is associated with a number of placenta-mediated diseases such as preeclampsia. The aim of this study was to evaluate the plasma level of homocysteine and its association with severity of preeclampsia. A case-control study was performed with 32 mild preeclamptic patients, 25 severe preeclamptic patients, 16 eclamptic patients and 34 controls. Maternal plasma homocysteine concentration was measured prospectively at antenatal period by high-performance liquid chromatography. There were no significant differences in demographic characteristics between the study and control groups. Mean plasma levels of homocysteine in women with severe preeclampsia (16.7 +/- 10.1 micromol/l, mean +/- S.D., n = 25) and eclampsia (16.5 +/- 9.6 micromol/l, mean +/- S.D., n = 16) were significantly higher than those in mild preeclampsia (7.7 +/- 2.4 micromol/l, mean +/- S.D., n = 32) and controls (6.7 +/- 1.6 micromol/l, mean +/- S.D., n = 34) (p < 0.0001). It should be noted that plasma levels of homocysteine are not significantly different between mild preeclampsia and controls. In conclusion, plasma homocysteine concentrations are increased in severe preeclampsia and eclampsia, but not in mild preeclampsia.     

Kawasaki disease and oxidative metabolism

The plasmid lipid peroxidation products: malonyldialdehyde (MDA), organic hydroperoxides (OHP) and zinc peripheral values were analysed in seven children with Kawasaki disease, in the acute phase, before and after treatment with intravenous immunoglobulins. In the acute phase, plasma levels of MDA (2.95 +/- 0.30 mumol/l, control group: 2.52 +/- 0.08 mumol/l) and OHP (235 +/- 65 mumol/l, control group: 120 +/- 10) were increased (p less than 0.05 and p less than 0.01). Moreover, plasma zinc levels were significantly decreased (10 +/- 2.15 mumol/l versus 15.6 +/- 2.5 mumol/l in control group, p less than 0.05). After treatment with immunoglobulins, MDA, OHP and plasma zinc levels returned to normal. The parallel normalisation of clinical injury draws attention to the possible role of oxygen intermediates in connective tissue degradation and in the pathogenesis of vascular abnormalities in Kawasaki disease.     

不同程度慢性肾功能不全患者体内氧化损伤状态的研究

目的 :观察不同程度的慢性肾功能不全 (CRI)患者体内脂质过氧化物和抗氧化酶活性的改变 ,探讨氧化损伤状态和抗氧化系统变化在 CRI发病机制中的作用 ,以及它们与肾功能改变的关系。方法 :采用化学比色法 ,对 36例 CRI患者、12例血液透析患者和 16例正常人的血清丙二醛 (MDA)、谷胱甘肽过氧化物酶(GSH Px)及血清超氧化物歧化酶 (SOD)的含量进行了检测。结果 :36例 CRI患者、12例血液透析患者的血清 MDA水平均明显高于正常对照组〔(4.0 6± 0 .6 7) μmol/ L〕,有显著性差异 (P<0 .0 1) ;GSH Px均明显低于正常对照组〔(12 0 .6 3± 2 7.5 7)× 10 4 U/ L〕,有显著性差异 (P<0 .0 1) ,血清 SOD亦明显高于正常对照组〔(110 .30± 18.6 0 ) k NU / L〕,有显著性差异 (P<0 .0 1)。 36例 CRI患者 SOD、GSH Px和 MDA含量与内生肌酐清除率 (CCr)均呈密切相关 (r G=0 .6 8,P<0 .0 1;r M=0 .5 2 ,P<0 .0 1;r S=0 .4 4 ,P<0 .0 5 )。结论 :自由基、脂质过氧化损伤和抗氧化系统的缺陷在慢性肾功能不全的发病机制中起重要作用 ,并且与肾功能的改变密切相关 ,这些酶活性还可作为临床判断病情严重程度的指标。     

Antioxidant potential and transferrin, ceruloplasmin, and lipid peroxidation levels in women with preeclampsia.

BACKGROUND: The aim of this study was to evaluate lipid peroxidation and antioxidant function in patients with preeclampsia and in normotensive pregnant women and to assess an association with the severity of the disease. METHODS: Twenty-one patients with mild preeclampsia, 15 patients with severe preeclampsia, and 19 normotensive pregnant women were included in the study. Plasma antioxidant potential (AOP) status, ceruloplasmin (Cp) and transferrin (Trf) levels as antioxidants, and malondialdehyde (MDA) levels as an indicator of lipid peroxidation were measured. RESULTS: Whereas the AOP and Trf levels of the severe and mild preeclampsia groups were found to be reduced, the MDA and Cp levels were increased compared with those of the normotensive pregnant group. There were statistically significant negative correlations between AOP and MDA in all groups. No differences were observed between the groups with severe and mild preeclampsia with respect to these analytes. CONCLUSION: Our findings suggest that lipid peroxidation may be an important factor in the pathogenesis of preeclampsia and that plasma antioxidants and oxidants are altered in preeclampsia. However, these findings may not be useful in distinguishing women with severe and mild preeclampsia.     

Oxidizability of apolipoprotein B-containing lipoproteins and serum paraoxonase/arylesterase activities in preeclampsia

OBJECTIVES: Lipoprotein oxidation has been implicated in the pathogenesis of preeclampsia and paraoxonase, an antioxidant enzyme shown to protect lipoproteins from being oxidized. The aim of the present study was to evaluate oxidizability of apolipoprotein B-containing lipoproteins and serum paraoxonase/arylesterase activities in preeclampsia. DESIGN AND METHODS: Twenty-one women with mild preeclampsia, 21 women with severe preeclampsia, and 20 women with normal uncomplicated pregnancy were included in this study. Serum malondialdehyde (MDA) level, an indicator of lipid peroxidation, was measured by high-performance liquid chromatography (HPLC). The oxidizability of apolipoprotein B-containing lipoproteins was evaluated by copper-induced in vitro peroxidation of the isolated fraction of apolipoprotein B-containing lipoproteins coupled with the thiobarbituric acid-reactive substances assay and expressed as the difference between copper-treated MDA and basal MDA (DeltaMDA). The serum paraoxonase and arylesterase activities were determined spectrophotometrically. RESULTS: Serum MDA and DeltaMDA levels of apolipoprotein B-containing lipoproteins were significantly higher in both mild and severe preeclampsia groups than in the normal pregnant group. Serum paraoxonase and arylesterase activities were not significantly different among the study groups. CONCLUSIONS: Enhancement in oxidizability of apolipoprotein B-containing lipoproteins accompanying with dyslipidemia and increased serum MDA levels suggests that those lipoproteins play a role in the pathogenesis of preeclampsia. Further studies are needed to investigate serum paraoxonase activity in women with normal pregnancies and preeclampsia.     

Lipid peroxidation and osmotic fragility of red blood cells in sleep-apnea patients

BACKGROUND: Obstructive sleep apnea (OSA) refers to the occurrence of episodes of complete or partial pharyngeal obstruction with oxyhemoglobin desaturation during sleep. These hypoxia/reoxygenation episodes may cause generation of reactive oxygen species. Reactive oxygen species are toxic to biomembranes and may lead to the peroxidation of lipids. We tested the hypothesis that obstructive sleep apnea is linked to increased oxidative stress and lipid peroxidation. In order to identify target tissue/cell damage, we studied the osmotic fragility of red blood cells. METHODS: Six subjects polysomnographically diagnosed as obstructive sleep apnea syndrome and 10 controls were included. After all subjects gave written informed consent, blood samples were collected in the morning between 08:00 and 09:00 a.m. following polysomnography. Blood samples were immediately transferred to the laboratory. Glutathione, lipid peroxidation and osmotic fragility of red blood cells were measured manually. RESULTS: Mean glutathione and lipid peroxidation concentrations of patients were not different than those of control subjects (105.6+/-38.6 U/g Hb and 3.1+/-2.3 nmol MDA/l vs. 100.6+/-62.1 U/g Hb and 3.2+/-2.8 nmol MDA/l, respectively). In both groups, osmotic fragility of red blood cells was not changed. CONCLUSION: The present study failed to support the hypothesis that obstructive sleep apnea is linked with increased oxidative stress and lipid peroxidation.     

The changes of trace elements,malondialdehyde levels and superoxide dismutase activities in pregnancy with or without preeclampsia

OBJECTIVES: Increased free radical activity and lipid peroxidation may be implicated in the pathogenesis of preeclampsia. This study was initiated to assess antioxidant enzyme and trace metals's status in preeclampsia. DESIGN AND METHODS: The comparison was made between the pregnant women with or without preeclampsia and healthy controls in this study. Samples were obtained from 24 normal nonpregnant (controls), 30 normal pregnant and 21 preeclamptic women in the third trimester. Lipid peroxidation end product, malondialdehyde (MDA), free radical scavenging enzyme activity, superoxide dismutase (SOD) and serum zinc (Zn), copper (Cu) levels were measured in either plasma/serum or erythrocytes of patients. Data were analyzed statistically using Student's t-test. RESULTS: In the preeclamptic group malondialdehyde, Cu levels were significantly increased, while Zn and SOD levels were significantly decreased compared to normal control group and healthy pregnant women. CONCLUSIONS: Our findings give support that radical scavenging SOD is consumed by the increased lipid peroxidation in preeclampsia. This data may indicate an involvement of free radicals in the pathophysiology of preeclampsia. This study suggests a relationship between increased MDA, Cu levels and decreased SOD, Zn levels in pregnancy and preeclampsia.     

Plasma malondialdehyde (MDA) levels in breast and lung cancer patients

OBJECTIVE: To measure the levels of malondialdehyde (MDA), a marker of lipid peroxidation, in patients with breast and lung cancer. METHOD: Analysis of plasma MDA, and serum uric acid, albumin, cholesterol and triglycerides in 26 breast and 12 lung cancer patients and 41 healthy controls. The effects of age, body mass index (BMI), and menopausal status on plasma MDA were evaluated in the 26 patients with breast cancer. RESULTS: Plasma MDA levels in cancer patients were significantly higher than those in controls (P < 0.001). Average MDA levels were 6.33 micromol/L in breast cancer patients and 5.87 micromol/L in lung cancer patients. There was no correlation between MDA and triglyceride levels in either controls or cases. There was no correlation between MDA and cholesterol levels in patients with breast cancer, but there was a correlation in patients with lung cancer. Albumin levels did not differ significantly between controls and cases (P > 0.05), but uric acid levels in breast cancer patients were significantly higher than those of controls (P < 0.01). CONCLUSION: The results of this study provide further evidence of the relationship between lipid peroxidation and cancer and should contribute to the interpretation of epidemiological studies in this area and the planning of future research.     

Malondialdehyde levels in sperm and seminal plasma of asthenozoospermic and its relationship with semen parameters

BACKGROUND: Toxic lipid peroxides are known to cause various impairments of sperm cells and may play a major role in the etiology of male infertility. We determined the level of lipid peroxidation as indicated by malondialdehyde (MDA) in the spermatozoa and seminal plasma of asthenozoospermic and normozoospermic males. METHODS: MDA of spermatozoa and seminal plasma was determined in 35 asthenozoospermic and 15 normozoospermic men by spectrofluorometry. Semen analysis was done according to the WHO standard. RESULTS: MDA concentration in the spermatozoa of asthenozoospermic was significantly higher than in normozoospermic males (0.14+/-0.059 and 0.09+/-0.04 nmol/10 x 10(6) spermatozoa respectively). The mean+/-S.D. MDA value in the seminal plasma of asthenozoospermic and normozoospermic were 1.35+/-0.42 and 1.2+/-0.3 nmol/ml seminal plasma respectively. CONCLUSIONS: Lipid peroxidation has a deleterious effect on the semen quality and MDA is an index of lipid peroxidation which may be a diagnostic tool for the analysis of infertility in the asthenozoospermic patients.     

Decreased glutathione-S-transferase activity: diagnostic and protective role in vivax malaria

OBJECTIVES: The study was undertaken to establish data on the comparative status of antioxidant enzyme GST activity, levels of lipid peroxidation and catalase activity during pathology of Plasmodium vivax malaria in Indian population. We investigated whether serum and plasma glutathione-S-transferase activity in vivax patients are unique to the disease or act as one of the important antioxidant marker for diagnostic potential and candidate for chemoprevention. METHODS: We measured activity of antioxidant enzyme GST, levels of lipid peroxidation and catalase activity during vivax infection. RESULTS: Mean activity of antioxidant enzyme GST in patients serum and plasma were less (6.43 and 5.65 IU/L respectively) than healthy subjects (11.65 and 10.09 IU/L respectively). Lipid peroxidation level and catalase activity of patients (1.77 micromol/L and 29.64 U/mL) with vivax malaria were higher than those of healthy subjects (1.03 micromol/L and 10.87 U/mL). GST activity in serum and plasma was inversely correlated with age in case of vivax patient and were found significant (R2=0.1907 and 0.1605 and p<0.0007 and p<0.01). CONCLUSIONS: In view of the present findings we suggest that GST, lipid peroxidation and catalase evaluation may be considered to be reliable biochemical markers and possess promising rational for diagnostic and therapeutic potential in vivax malaria. Decreasing GST activity and elevated activity of lipid peroxidation and catalase may play important roles in host defence mechanisms against vivax infection by up-regulating oxidative defence mechanisms.     

The role of oxidative stress in bronchoconstriction due to occupational sulfur dioxide exposure

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.     

Urinary hydrogen peroxide: a probable marker of oxidative stress in malignancy

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.     

Serum adenosine deaminase activity in women with hyperemesis gravidarum

BACKGROUND: Serum adenosine deaminase (ADA) activity increases in diseases where cellular immunity is stimulated. Since hyperemesis gravidarum is characterized by enhanced cell-mediated immunity, serum ADA activity may be altered. The present study evaluated the relation between serum ADA activity and changes in cell-mediated immunity as causes of changes in ADA activity in hyperemesis gravidarum. METHODS: Serum activities of total ADA and its isoenzymes, ADA1 and ADA2, were measured in women with hyperemesis gravidarum (n = 24) and normal pregnancies (n = 24). Peripheral blood lymphocyte and monocyte counts were also measured. RESULTS: In hyperemesis gravidarum, serum total ADA and ADA2 activities averaged 16.8 +/- 0.5 and 13.3 +/- 0.7 U/l, respectively, which were significantly higher than those in normal pregnancies (10.2 +/- 0.5 and 7.8 +/- 0.5 U/l, respectively) (p < 0.05). The mean values for ADA1 activity in women with hyperemesis gravidarum and normal pregnancies were similar. The increase in total ADA activity was accompanied by the increase in lymphocyte and monocyte counts. CONCLUSIONS: These results suggest that increased serum total ADA activity reflects increases in ADA2 activity, which may be at least in part attributed to enhanced cell-mediated immunity in hyperemesis gravidarum.     

High-performance liquid chromatographic detection of lipid peroxidation in human seminal plasma and its application to male infertility

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.     

Effects of magnesium sulfate on lipid peroxidation and blood pressure regulators in preeclampsia

OBJECTIVES: To investigate the status of lipid peroxidation and serum levels of several vasoactive substances in preeclamptic (PE) pregnant women before and during treatment with magnesium sulfate (MgSO(4)). DESIGN AND METHODS: The study population included 16 PE women. Circulating levels of malondialdehyde (MDA), endothelin 1 (ET-1), nitric oxide (NO) metabolites, and calcitonin gene-related peptide (CGRP) were measured before (at admission) and during MgSO(4) treatment (at delivery and 24 h postpartum). RESULTS: At admission systolic and diastolic blood pressures were 157 +/- 3 mm Hg and 106 +/- 2 mm Hg, respectively, and decreased significantly during treatment at delivery and 24 h postpartum (P < 0.0001). Before treatment, serum MDA concentrations were 0.383 +/- 0.037 micromol/L, and decreased significantly during MgSO(4) administration at delivery and 24 h postpartum (P < 0.0001). In contrast, serum ET-1 levels at 24 h postpartum were significantly higher as compared with those observed before treatment (79 +/- 3 versus 65 +/- 2 pg/mL, P = 0.002). Serum NO metabolite concentrations were 26 +/- 3 micromol/L, and no significant changes were observed during treatment. Serum levels of CGRP were 50 +/- 3 pg/mL at admission, and increased significantly at partum (P < 0.001). Serum ET-1 correlated negatively with NO metabolites before treatment (r = -0.69, P = 0.002), but not during treatment. In contrast, ET-1 correlated positively with serum CGRP levels during treatment (r = 0.73, P = 0.002 and r = 0.71, P = 0.002, at delivery and 24 h postpartum, respectively), but not before treatment. CONCLUSIONS: This study demonstrates that MgSO(4) administration to PE pregnant women induced significant changes in lipid peroxidation, production of ET-1 and CGRP.     

Oxidative stress in patients with non-complicated malaria

AIM: To compare oxidative stress in adults with non-complicated malaria and healthy controls. METHODOLOGY: We measured malondialdehyde (MDA), total antioxidant status (TAS), catalase, superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX). Oxidative stress was calculated based on MDA/TAS, MDA/GSH-PX and SOD/catalase indexes. RESULTS: Mean MDA in patients was 3.9 micromol/L (controls = 1.3 micromol/L). Mean TAS was 0.9 mmol/L in patients and controls. Malaria patients had less catalase activity when compared to controls (209.4 vs. 320.4 k/gr), while SOD and GSH-PX activity was higher (79.4 U/mL, 11,884.2U/L vs. 54.3 U/mL, 9,672.6 U/L). MDA/TAS index was 3.5 fold more in patients than in controls, MDA/GSH-PX and SOD/catalase indexes were increased by 6 and 2.8 fold. MDA levels and MDA/TAS index showed no differences according to malarial history, parasitaemia, Plasmodium species, parasite's stage, place of residence and drinking or smoking habits. CONCLUSIONS: During acute non-complicated P. falciparum or P. vivax malaria, we observed high oxidative stress. This resulted from lipid peroxidation rather than from a reduced TAS. We propose MDA/TAS index as a useful marker of oxidative stress during malaria infection.     

Atherosclerosis risk factors related to hemodialysis duration and erythropoietin therapy.

Patients undergoing hemodialysis are at risk for atherosclerosis and its complications. The aim of this study was to examine the effect of erythropoietin therapy and hemodialysis duration on some of the atherosclerotis risk factors. The patients were divided into four groups: I: patients undergoing hemodialysis for less than 10 years (n=22); II: patients undergoing hemodialysis for more than 10 years (n=17); III: patients on no erythropoietin (n=21); IV: patients on erythropoeitin therapy (n=18). A control group of 20 subjects was also examined. Triglycerides, total cholesterol, low-density lipoprotein and high-density lipoprotein, lipoprotein(a), apolipoprotein-A1, apolipoprotein-B and lipid peroxidation were examined. There was a significant increase in triglycerides, to 2.59+/-1.2 mmol/l (p<0.001) and in lipid peroxidation in hemodialysis patients, to 5.02+/-0.9 micromol/l vs. controls (p<0.001). Significantly elevated triglycerides and lipid peroxidation levels were found in the patients with longer hemodialysis duration. Triglycerides were elevated in group II vs. group I, to 2.90+/-1.0 mmol/l. (p<0.05). Lipid peroxidation in group II, 5.40+/-1.0 micromol/l, showed significant difference compared to group I (p<0.05). Erythropoietin treatment did not affect any of the examined parameters. These results indicate increased risk for atherosclerosis related to hemodialysis duration. Besides the renal disease itself, hemodialysis may also be one of the risk factors for atherosclerosis.     

Determination of nitrite plus nitrate and malondialdehyde in human plasma: analytical performance and the effect of smoking and exercise.

The aim of this study was to evaluate the analytical performance and clinical usefulness of spectrophotometric assays for the measurement of the plasma levels of nitrite plus nitrate (NOx), and malondialdehyde (MDA), as an index of nitric oxide release and lipid peroxidation, respectively. We studied 30 healthy sedentary volunteers, 12 endurance athletes and 12 regular heavy smokers. The lower limit of quantification for plasma NOx concentration was 1 micromol/l, and linearity was observed from 1 to 40 micromol/l of NOx concentration. Variation in replicate samples within or between days was always below 5%. NOx levels were significantly higher in athletes compared to both control subjects and smokers (p<0.05 and p<0.001, respectively), as well as in healthy subjects compared to smokers (p<0.05). The analytical limit of quantification for plasma MDA concentration was 0.03 micromol/l, and linearity was observed from 0.03 to 20 micromol/l of MDA concentration. Variation in replicate samples within or between runs was <5%. Mean MDA concentration was significantly higher in smokers compared to control subjects and athletes (p<0.001). A significant inverse relationship (p<0.001) was observed when comparing NOx with MDA (r=-0.49) or LDL levels (r=-0.30) in the total population. The assays evaluated in this study proved to be sensitive, specific and practicable, and therefore suitable for routine application in clinical chemistry laboratories and/or physiopathological studies involving human blood samples.     

Elevated plasma glutathione peroxidase concentration in acute severe asthma: comparison with plasma glutathione peroxidase activity, selenium and malondialdehyde

OBJECTIVE: To investigate plasma glutathione peroxidase concentration, glutathione peroxidase activity, plasma selenium and oxidative stress in acute severe asthma. MATERIAL AND METHODS: The study was case-control in design, with cases presenting to the emergency department with acute severe asthma and controls randomly selected from a larger cross-sectional study. Plasma malondialdehyde (MDA) was used as a measure of oxidative stress and plasma selenium was measured using ICP-MS. Glutathione peroxidase (GPx) activity was analysed using a colorimetric GPx assay and plasma GPx level was measured by enzyme-linked immunosorbent assay (ELISA). RESULTS: Fifteen cases [mean (range) predicted peak expiratory flow rate (PEFR) of 43% (20-69)] and 15 matched controls were recruited. MDA levels (mean+/-SD) were higher in acute asthma subjects (1.30+/-0.56 micromol/L) than in controls (0.86+/-0.53 micromol/L; p<0.05). There were no differences between cases and controls for selenium (99+/-34 microg/L versus 109+/-17 microg/L) or for GPx activity (39+/-25 nmol min(-1) mL(-1) versus 38+/-24 nmol min(-1) mL(-1)), however, GPx plasma levels measured by ELISA were higher in cases than controls (22.5+/-10.8 mg/L versus 13.8+/-7.3 mg/L; p<0.05). CONCLUSIONS: Patients with acute severe asthma demonstrated increased MDA levels but no differences in plasma selenium levels or GPx activity. GPx levels measured by ELISA were elevated in severe asthma. These results are consistent with an adaptive up-regulation of GPx to protect against oxidative stress.