Antioxidant Capacity In Patients Research Articles

The challenge of antioxidants to free radicals in periodontitis

Periodontal disease is a chronic adult condition. Bacteria implicated in the etiology of this disease causes destruction of connective tissue and bone. As a result of stimulation by bacterial antigen PMN produces free radicals via respiratory burst as a part of host response to infection. Patients with periodontal disease display increased PMN number and activity. This proliferation results in high degree of free radical release culminating in heightened oxidative damage to gingival tissues, periodontal ligament and alveolar bone. Damage mediated by free radicals can be mitigated by “ANTIOXIDANT DEFENSE SYSTEM “. Physiological alteration and pathological states produced by free radicals depend on disequilibrium between free radical production and antioxidant levels leading to oxidative stress.Hence this study has been designed to estimate the TOTAL ANTIOXIDANT CAPACITY in patients with PERIODONTITIS and healthy control subjects

Influence of polymorphism of glutathione S-transferase T1 on Chinese infertile patients with varicocele

To investigate the influence of glutathione S-transferase T1 (GSTT1) gene polymorphism on Chinese infertile patients with varicocele, 63 infertile patients with varicocele and 54 healthy fertile controls were recruited in this case-control study. Our results show that oxidative damage may be the cause of infertility in patients with varicocele, and GSTT1 null genotype predisposes to over oxidative damage to spermatocytes of infertile patients with varicocele.

Attenuation of Oxidative Stress After Varicocelectomy in Subfertile Patients With Varicocele

We examined changes due to oxidative damage to spermatozoa and alterations in antioxidant capacity in subfertile patients with varicocele before and after varicocelectomy in a prospective study. A total of 30 young subfertile male patients with varicocele were recruited in this study. Varicocele was diagnosed by physical examination and Doppler ultrasound. Semen analysis was performed in the 30 patients before and 6 months after varicocelectomy using a computer assisted semen analyzer. The parameters for evaluating oxidative stress changes were 4977 bp deletion of mitochondrial DNA in sperm, as detected by polymerase chain reaction, the 8-OHdG (8-hydroxy-2'-deoxyguanosine) content in spermatozoa DNA, as measured by a high performance liquid chromatography electrochemical method, and seminal plasma protein thiols and ascorbic acid, as measured by spectrophotometric methods. Semen quality, including motility, morphology and sperm density, was improved in 22 patients (73.3%) after varicocelectomy. The incidence of 4977 bp deletion of mitochondrial DNA in sperm was 40% (12 of 30 patients) and 13.3% (4 of 30) before and after surgery, respectively. Mean +/- SD 8-OHdG content in sperm DNA, and seminal plasma protein thiols and ascorbic acid were 10.27 +/- 2.24/10(5) 2'-deoxyguanosine, 0.77 +/- 0.75 nmole/ml and 1.87 +/- 0.40 mg/dl before operation, and 5.95 +/- 1.46/10(5) 2'-deoxyguanosine, 3.00 +/- 1.17 nmole/ml and 3.12 +/- 0.94 mg/dl after surgery, respectively. The incidence of 4977 bp deletion of mitochondrial DNA in sperm and the level of 8-OHdG in sperm DNA were decreased, and seminal plasma protein thiols and ascorbic acid were increased significantly in all 30 patients after varicocelectomy. Also, in the 8 patients in whom semen quality did not improve after surgery a significant decrease in 8-OHdG in sperm DNA, and a significant increase in seminal plasma protein thiols and ascorbic acid were observed. Subfertile patients with varicocele had a significant decrease in oxidative damage in sperm DNA and an increase in antioxidant capacity in seminal plasma after varicocelectomy, indicating that surgery is effective treatment in such patients.

Relationship between DNA damage and total antioxidant capacity in patients with transitional meningioma

Purpose The purpose of this study was to assess oxidative DNA damage and total antioxidant capacity (TAC) in patients with transitional meningioma (TM) and to compare the results with normal brain tissues. Patients and methods Oxidative DNA damage and TAC were evaluated in TM extracted from 22 patients and in normal brain tissues of 15 subjects who underwent autopsy within first 4 h of death. Oxidative DNA damage was assessed by measuring 8-hydroxy-2-deoxyguanosine (8-OH-dG) using the 8-OH-dG enzyme immunoassay kit, a quantitative assay for 8-OH-dG, and TAC was analyzed using the ImAnOx colorimetric test system for the determination of antioxidative capacity. The results were compared between two groups and any correlation between 8-OH-dG and TAC was sought. Results The median level of TAC in TM (135 nmol/g wet tissue) was remarkably lower than in normal brain tissue (298 nmol/g wet tissue). The difference was statistically significant ( p = 0.00001). In contrast, oxidative DNA damage was significantly higher in patients with TM (71.61 ng/g wet tissue) than in controls (34.71 ng/g wet tissue). Again, the difference was statistically significant ( p = 0.00001). We also found a negative correlation between oxidative DNA damage and TAC ( p < 0.001). Conclusion These findings show that the degree of oxidative DNA damage is increased and TAC is decreased in TM and oxidative DNA damage is negatively correlated with the levels of TAC.

Ascorbic Acid Alleviates Pancreatic Damage Induced by Dibutyltin Dichloride (DBTC) in Rats

PurposeBecause previous studies have reported depleted antioxidant capacity in patients with chronic pancreatitis (CP), prevention of free radical production has gained importance in antifibrotic treatment strategies for CP. The aim of this study was to investigate the effects of ascorbic acid on oxidative capacity and pancreatic damage in experimental CP.Materials and MethodsCP was induced in male Sprague-Dawley rats by infusion of dibutyltin dichloride (DBTC) into the tail vein. Ascorbic acid was given intraperitoneally at a daily dose of 10 mg/kg body weight. The treatment groups were as follows: group 1, DBTC plus intraperitoneal physiologic saline; group 2, DBTC plus intraperitoneal ascorbic acid; group 3, solvent plus intraperitoneal physiologic saline; group 4, no operation plus intraperitoneal physiologic saline. Each group contained 15 animals. Treatment was started after CP was established. After 4 weeks of treatment, serum hyaluronic acid and laminin levels were determined by radioimmunoassay, pancreatic tissue oxidative stress was analyzed, and the degree of pancreatic damage was determined.ResultsAscorbic acid treatment markedly increased superoxide dismutase (SOD) activity and decreased malondialdehyde (MDA) concentrations in pancreatic tissue (p < 0.01 for both). Significant serum hyaluronic acid and laminin reductions were observed in group 2 as compared with group 1 (p < 0.05). However, the serum hyaluronic acid and laminin levels remained elevated when compared with those of groups 3 and 4 (p < 0.05). Histopathologic scores were also lower in animals with CP that underwent ascorbic acid-treatment (p < 0.05).ConclusionAscorbic acid treatment alleviated the degree of oxidative stress and pancreatic damage in rat CP. Antioxidant treatment might be considered a potential option to improve the pathologic process in CP.

Antioxidant Treatment with Taurine Ameliorates Chronic Pancreatitis in an Experimental Rat Model

Based on the results of recent studies that reported depleted antioxidant capacity in patients with chronic pancreatitis (CP), prevention of free radical production has gained importance in antifibrotic treatment strategies in CP. The aim of this study was to investigate the effects of taurine on oxidative capacity and fibrosis in experimental chronic rat pancreatic fibrosis. CP was induced in male Sprague-Dawley rats by intraductal trinitrobenzene sulfonic acid (TNBS) dissolved in ethanol. Taurine was given intraperitoneally at a concentration of 1000 mg/kg. The treatment groups were as follows: group 1, TNBS plus normal saline (NS); group 2, TNBS plus taurine; group 3, ethanol plus NS; and group 4, NS plus NS. Each group contained 15 animals. Treatment was started after established CP. After 4 weeks of treatment, markers of oxidative stress and the degree of pancreatic fibrosis were determined. The amount of weight loss was significantly lower in the taurine-treated group with CP (P < 0.002). Tissue malondialdehyde levels increased and superoxide dismutase and glutathione peroxidase activities decreased significantly after treatment as well (P < 0.001). Histopathologic scores were also lower in taurine-treated animals with CP (P < 0.005). Taurine treatment improved the degree of oxidative stress and fibrosis in rat CP. Antioxidant treatment might be considered a novel option to alleviate the fibrotic process in CP.

Total Antioxidant Capacity in Children with Acute Appendicitis

This study aimed to investigate antioxidant capacity by using a novel automated method in children with acute appendicitis. Blood samples were obtained from consecutive patients with acute appendicitis (appendicitis group, n = 12) and acute abdominal pain due to non surgical disease (non-appendicitis group, n = 11), and from patients with inguinal hernia (healthy group, n = 12) as the control group. At admission, total antioxidant capacity (TAC) levels of plasma were evaluated in all patients by a method recently developed by Erel. Four other major individual plasma antioxidant components, the levels of total protein, albumin, uric acid and bilirubin, were also evaluated. Total antioxidant capacity in patients with acute appendicitis was statistically compared with the two other groups. While the TAC level in the appendicitis group was significantly greater than in the non-appendicitis group, no significant difference was found in healthy groups (p < 0.05, p > 0.05, 1.94 +/- 0.38, 1.40 +/- 0.36, and 1.99 +/- 0.35 respectively). Individual components of total antioxidant capacity, i.e. total protein, albumin, uric acid and bilirubin concentrations, were also higher in the patients with acute appendicitis than those of the other two control groups. Our data show that children with acute appendicitis do not have deficient blood plasma antioxidant capacity. These results provide evidence that acute appendicitis results in more induction of antioxidative response than non-surgical diseases.

Tu-P10:500 Decreased serum antioxidant capacity in patients with diabetes and atherosclerosis can be ameliorated after vitamin C and E administration

Tu-P10:500 Decreased serum antioxidant capacity in patients with diabetes and atherosclerosis can be ameliorated after vitamin C and E administration

LDL susceptibility to oxidation and HDL antioxidant capacity in patients with renal failure

Objectives This study examines the susceptibility to oxidation and the ability to stimulate reactive oxygen species of LDL from hemodialysis (HD) and continuous ambulatory peritoneal dialysis (CAPD) patients. It was also designed to evaluate the antioxidant activity of HDL from uremic patients. Design and methods Lipoprotein properties were determined in 28 HD patients, 30 CAPD patients and 30 control subjects by spectrophotometric, chemiluminescence and electrophoresis methods. Results CAPD LDL were more resistant to oxidation than control LDL. HD and control LDL, in contrast to CAPD LDL, stimulated reactive oxygen species generation in granulocytes. The HDL ability to protect LDL against oxidation was impaired in renal patients. Conclusions The risk of atherosclerosis development in patients with renal failure does not appear to be related to less resistance of LDL to oxidation, but rather to the decreased HDL antioxidant capacity.

Increased seminal reactive oxygen species levels in patients with varicoceles correlate with varicocele grade but not with testis size

Increased levels of reactive oxygen species (ROS) are associated with clinical varicoceles; however, its correlation with varicocele grade and testis size is unknown. In our study, seminal ROS levels showed significant correlation with left varicocele grade and significantly elevated seminal ROS levels were seen in men with left varicocele grade 2 and 3 compared to grade 1.

Total Antioxidant Status and Erythrocyte Superoxide Dismutase Activity in Patients with Chronic Hepatitis B and C

Damage of hepatitis B virus (HBV) and hepatitis C virus (HCV)-infected hepatocytes is mediated by both a direct cytopathic effect of the viruses and by immunologic response of T-cells, However, other mechanisms such as oxidative stress, may also be involved in cellular damage. We conducted a study to investigate the status of superoxide dismutase activity (SOD) and the total antioxidant status (TAS) in a consecutive cohort of patients infected with HBV and HCV infections, including HBV patients in the chronic inactive state of the disease. The latter were included in an attempt to determine whether antioxidant status is affected even in cases where an obvious viral activity is absent. TAS and SOD were measured in 55 patients (43 HBV, 12 HCV) and 25 healthy controls. 17 out of 43 patients had chronic inactive HBV state, 15 had chronic hepatitis Band 11 had HBV-related cirrhosis. In the HCV group, 6 patients had chronic hepatitis C and 6 HCV-related cirrhosis. Erythrocyte SOD activity was determined in haemolysate from red blood cells using a kinetic spectrophotometer method. TAS was measured by a colorimetric assay. The mean TAS and SOD values in the total number of patients (1.20±0.12 mmol/L and 1040±255 Ulg Hb, respectively) were significantly lower (p&lt;0.001) compared to healthy controls (1.57±0.13 mmol/L and 1491±420 D/g Hb), Comparisons between groups showed significantly lower (p&lt;0.001) TAS and SOD values in each subgroup of patients compared to healthy controls. A significant positive correlation was found between TAS and SOD in the total number ofpatients (n= 55, p&lt;0.01), in the chronic hepatitis group (n=21, p=0.01) and in the total group of HBV patients (n=43, p&lt;0.01). We demonstrated a significant reduced antioxidant capacity in patients with chronic HBV and HCV as indicated by low TAS and SOD. These findings were independent of the virological, biochemical and clinical status of the patients, including those with chronic inactive HBV state. This could suggest that the tissue-related consequences of oxidative stress might start from the inactive stage of liver viral diseases. However, our observations should be viewed with caution and need to be tested in a larger numbers of patients in order to determine prospectively whether these findings have pathophysiological and/or clinical significance.

Preventive effects of diets supplemented with sweetie fruits in hypercholesterolemic patients suffering from coronary artery disease

Background. Diets rich in vegetables and fruits prevent development of atherosclerosis. Objective. To investigate the preventive effects of diets supplemented with a new kind of citrus fruit—pummelo–grapefruit hybrid in hypercholesterolemic patients suffering from coronary artery disease (CAD). Subjects and methods. Sixty-six hypercholesterolemic volunteers after coronary bypass surgery ages 47–68 years were randomly divided into two experimental (EG1 and EG2) groups and one control (CG) group, 22 each. The diets of the patients of the experimental groups (EG1 and EG2) were supplemented with one or two peeled sweeties, respectively. A comprehensive clinical investigation of all 66 patients was done. Blood samples were collected before and after the investigation for a wide range of laboratory tests. Results. A high content of dietary fibers and antioxidant compounds in peeled sweeties was found. After 30 days of the investigation, peeled sweeties-supplemented diets have decreased plasma lipids levels in EG1 and EG2 vs. CG group: (a) total cholesterol (TC)—7.38 vs. 8.08 mmol/L, − 8.7%, and 6.78 vs. 8.08. mmol/L, −16.1%, respectively; (b) low-density lipoprotein cholesterol (LDL-C)—5.65 vs. 6.39 mmol/L, − 1.6%, and 5.04 vs. 6.39 mmol/L, −21.2%, respectively; (c) triglycerides (TG)—2.01 vs. 2.27 mmol/L, −11.5%, and 1.71 vs. 2.27 mmol/L, −24.7%, respectively. In addition, a significant increase in the plasma antioxidant capacity in EG2, and to a lesser degree in EG1 groups, was observed. No changes in the studied indices in the patients of the CG were detected. Conclusion. Peeled sweeties have high contents of dietary fibers and antioxidant compounds. Diets supplemented with peeled sweeties positively influence plasma lipid metabolism and plasma antioxidant capacity in patients suffering from hypercholesterolemia. Therefore, the addition of peeled sweeties to a generally accepted antiatherosclerotic diet may be beneficial in prevention of atherosclerosis, mainly in hypercholesterolemic patients.

Total antioxidant capacity in patients with varicoceles

Objective To explore a possible molecular defect linked to infertility, studying total antioxidant capacity (TAC) of seminal plasma in varicocele (VAR). Design Case-series study. Setting Volunteers in an academic research environment and out-patients in clinical service. Patient(s) Twenty-five VAR patients (9 oligospermic and 16 normospermic) vs 24 non-VAR controls (7 subjects with idiopathic oligospermia and 17 normospermic subjects). Intervention(s) Evaluation of seminal plasma TAC. Main outcome measure(s) TAC was measured using myoglobin, as a source of radicals, which interact with a chromogen 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate) (ABTS), whose radical cation is spectroscopically detectable. The latency phase (Lag) in the accumulation of ABTS cation is proportional to antioxidant concentration. Result(s) Lag showed significantly greater values in the all VAR patients vs non-VAR subjects. Oligospermic-VAR patients showed the greatest values. Lag and sperm motility significantly correlated in VAR normospermic patients. Follicle-stimulating hormone (FSH) showed significant inverse association with Lag in same group. Conclusion(s) The augmented Lag values could indicate an ineffective utilization of antioxidants in oligospermic-VAR, while in normo-VAR the direct correlation between TAC and motility suggest a potential protective role toward sperm motility. In the same group, the inverse correlation with FSH suggests that greater FSH levels induce a better utilization of antioxidants by spermatozoa.

Urinary Nitrite/Nitrate Concentrations and Total Antioxidant Capacity in Patients with Chronic Hepatitis C in Therapy with Interferon and Ribavirin

In this study we tried to elucidate the role of nitric oxide (NO) in chronic hepatitis C in relation to antioxidant status, since the mechanisms by which hepatitis C virus (HCV) causes cell damage and the factors underlying its resistance to therapy are not well understood.Before and after one and six months of therapy with α-interferon and ribavirin, we measured nitrite/nitrate urinary levels, total antioxidant capacity and selenium serum concentrations in 14 patients with chronic hepatitis C and in 9 healthy subjects. Before therapy, mean urinary nitrite/nitrate levels of patients were not different from those of healthy subjects, but after a 6-month treatment with α-interferon and ribavirin, these NO metabolites were higher in virologically negative patients (responders). Moreover, while no changes in selenium were observed in all patients, total antioxidant capacity was significantly higher in non-responders and well correlated with hyperuricemia (due to cell damage) observed in these subjects. Instead, uric acid decreased as free molecule in serum in responders, while we found the excretion of high NO levels as nitrite/nitrate.Our data allow us to hypothesize a role for NO as predictive of the success of therapy, since nitrite/nitrate increase in the urine of some patients precedes disappearance of the virus observed at the end of therapy.

Oxidative stress and antioxidant capacity in patients with inflammatory bowel disease

Objectives In this study we aimed to determine the levels of Glutathione peroxidase (GSH-Px) and Malondialdehyde (MDA) in patients with inflammatory bowel disease (IBD) to investigate their contribution to tissue injury in inflammatory bowel disease. Design and methods Forty-seven GSH-Px patients (35 with ulcerative colitis and 12 with Crohn’s disease) and 30 healthy controls were included in the study. Their plasma and MDA levels were compared using nonparametric statistical methods. Results Plasma GSH-Px levels of the patients group were significantly higher than the control group ( p < 0.001). There was no significant difference between patients and controls in view of plasma levels of MDA. Conclusions High levels of GSH-Px, which is response against oxidative stress, indicates the increase of free radicals in IBD, while normal plasma MDA levels suggest the clearance of free radicals without leading to lipid peroxidation. Our result reveals that there is an existing antioxidant capacity despite oxidative stress in patients with IBD.

Serum antioxidant capacity in neurological, psychiatric, renal diseases and cardiomyopathy.

The role of free radicals (FR) in the pathogenesis and in the progression of many diseases has been often discussed, but not widely investigated. However, the total antioxidant capacity in the serum seems to be of great evidence. Total antioxidant capacity was determined using oxygen absorbance capacity assay (ORAC) in serum of patients suffering from depression, schizophrenia, Alzheimer's disease (AD), anorexia nervosa, Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Aids-encephalopathy, diabetic polyneuropathy (PNP), cardiomyopathy (CM), renal disease, and healthy individuals as controls (C). The results showed that the total antioxidant capacity in serum decreased significantly (p < 0.01) by 24, 20, 13, and 17% for anorexia nervosa, Aids-encephalopathy, PNP and CM respectively. In serum of patients with renal disease significantly elevated antioxidant capacity was found. The data indicated that increased oxidative stress can be involved in the pathogenesis or in the progression of PNP and CM. Decrease of serum antioxidant capacity in patients with anorexia nervosa and Aids-encephalopathy are probably due primarily to malnutrition and secondly to insufficient antioxidant and immune system. In renal disease, the accumulation of urea in serum seems to be responsible for high antioxidant capacity. In contrast, there were no changes in PD, AD, depression syndrome and schizophrenia.

Oxidative damage to proteins and decrease of antioxidant capacity in patients with varicocele

To examine oxidative damage to blood proteins in the spermatic vein and seminal plasma antioxidant capacity of patients with varicocele, 30 young male patients with varicocele (group 1), 25 young male patients with subclinical varicocele (group 2), and 15 normal young males without varicocele (group 3) were recruited in this study. Varicocele and subclinical varicocele were confirmed by physical examination and Doppler ultrasonography. Blood samples were drawn from peripheral and spermatic veins before varicocelectomy. Plasma protein carbonyls were measured by a spectrophotometric assay after reacting with 2,4-dinitrophenylhydrazine. Protein thiols and ascorbic acid of seminal plasma were measured by spectrophotometric methods. We found that plasma protein carbonyls in the spermatic veins were significantly higher than those of corresponding peripheral veins in all 30 patients in group 1 and 12 patients in group 2 receiving varicocelectomy. Protein carbonyls in the spermatic veins of patients with varicocele (3.72 ± 0.56 nmole/mg protein) and patients with subclinical varicocele (3.50 ± 0.30 nmole/mg protein) were found to be higher than those of the control (2.35 ± 0.33 nmole/mg protein). Protein thiols were 0.97 ± 0.96, 1.50 ± 0.89, and 3.49 ± 0.81 nmole/ml, and ascorbic acid levels were 1.87 ± 0.42, 2.13 ± 0.24, and 2.38 ± 0.07 mg/dl, in seminal plasma of the patients in groups 1, 2, and 3, respectively. Seminal plasma protein thiols and ascorbic acid levels in group 1 were significantly lower than those in groups 2 and 3, respectively. These results indicate that oxidative stress in the patients with varicocele and subclinical varicocele was higher than that of the control. We suggest that plasma protein carbonyls, and protein thiols and ascorbic acid of seminal plasma are useful markers for the assessment of oxidative stress in patients with varicocele and subclinical varicocele.

Is there any relationship between plasma antioxidant capacity and lung function in smokers and in patients with chronic obstructive pulmonary disease?

BACKGROUNDIt has been suggested that oxidative stress is an important factor in the pathogenesis of chronic obstructive pulmonary disease (COPD). We have shown that an oxidant/antioxidant imbalance occurs in the...

Effect of eating on plasma radical-trapping antioxidant activity (TRAP) in patients with cirrhosis

Objectives: To ascertain the effects of eating on plasma antioxidant capacity in patients with liver disease. Design and methods: Eighteen cirrhotic patients were compared to 18 age and sex-matched controls. TRAP was measured by a fluorometric assay after a 12 h fast, and 60, 120, and 180 min after the study participants had taken a drink formula food. Results: In the fasting state, TRAP was higher in patients with alcoholic cirrhosis (847 ± 39 μmol/L, mean ± SEM) in comparison to patients with viral cirrhosis (653 ± 41) and to controls (758 ± 26) (p < 0.005). In cirrhotic patients, TRAP did not change in the post-absorptive state. In controls, TRAP decreased progressively, to a value of 719 ± 21 ( p < 0.02), and the AUC of the Δ-values of TRAP and of plasma insulin showed an inverse correlation (r = −0.52, p < 0.05). Conclusions: In normal subjects, but not in cirrhotics, TRAP decreases in the post-absorptive state, probably in relationship with the activation of metabolic pathways.

HDL composition and HDL antioxidant capacity in patients on regular haemodialysis

Recent evidence suggests that HDL can directly inhibit LDL oxidation, a key early stage in atherogenesis. Patients with chronic renal failure are at increased cardiovascular risk, have reduced HDL levels and altered HDL composition. We have therefore investigated whether compositional changes in HDL lead to decreased HDL antioxidant capacity in these patients. In comparison to control subject HDL, patient HDL contained less total cholesterol, cholesterol esters, phospholipids and α-tocopherol. LDL, HDL and LDL+HDL were standardised for protein and oxidised in the presence of Cu 2+. The rate of propagation during HDL oxidation was reduced in the patient group (3.28±0.65×10 −5 vs. 4.60±0.97×10 −5 abs. U/min, P<0.01). Lipid peroxide generation in patient HDL was decreased: 6.56±4.4 versus 13.42±7.0 nmol malondialdehyde (MDA)/mg HDL protein after 90 min and 14.45±3.8 versus 20.11±7.8 nmol MDA/mg HDL protein after 180 min. This is attributable to reduced HDL polyunsaturated fatty acid content in patients (0.53±0.12 vs. 0.72±0.16 mmol/g HDL, P<0.01). The inhibitory effect of HDL on LDL oxidation was similar: 71 and 33% for patient HDL compared to 68 and 31% for control HDL, after 90 and 180 min, respectively. Compositional changes of HDL in patients on haemodialysis did not affect the antioxidant capacity of HDL after standardisation for HDL protein. However, reduced HDL levels in vivo may result in reduced HDL antioxidant capacity in these patients.