Oxidative stress and cardiovascular disease in hemodialysis.
Explore the source record for details and available documents.
Acute-Phase Proteins↗
Biomedical subjects
M Boaz
Publications and source records attributed to M Boaz.
Secondary prevention with antioxidants of cardiovascular disease in endstage renal disease (SPACE): randomised placebo-controlled trial.
BACKGROUND: Excess cardiovascular mortality has been documented in chronic haemodialysis patients. Oxidative stress is greater in haemodialysis patients with prevalent cardiovascular disease than in those without, suggesting a role for oxidative stress in excess cardiovascular disease in haemodialysis. We investigated the effect of high-dose vitamin E supplementation on cardiovascular disease outcomes in haemodialysis patients with pre-existing cardiovascular disease. METHODS: Haemodialysis patients with pre-existing cardiovascular disease (n=196) aged 40-75 years at baseline from six dialysis centres were enrolled and randomised to receive 800 IU/day vitamin E or matching placebo. Patients were followed for a median 519 days. The primary endpoint was a composite variable consisting of: myocardial infarction (fatal and non-fatal), ischaemic stroke, peripheral vascular disease (excluding the arteriovenous fistula), and unstable angina. Secondary outcomes included each of the component outcomes, total mortality, and cardiovascular-disease mortality. FINDINGS: A total of 15 (16%) of the 97 patients assigned to vitamin E and 33 (33%) of the 99 patients assigned to placebo had a primary endpoint (relative risk 0.46 [95% CI 0.27-0.78], p=0.014). Five (5.1%) patients assigned to vitamin E and 17 (17.2%) patients assigned to placebo had myocardial infarction (0.3 [0.11-0.78], p=0.016). No significant differences in other secondary endpoints, cardiovascular disease, or total mortality were detected. INTERPRETATION: In haemodialysis patients with prevalent cardiovascular disease, supplementation with 800 IU/day vitamin E reduces composite cardiovascular disease endpoints and myocardial infarction.
Aged↗
Haemolysis in haemodialysis patients: evidence for impaired defence mechanisms against oxidative stress.
BACKGROUND: Uraemic patients have a decreased ability to withstand oxidative stress. It is postulated that their antioxidant capacity is reduced, yet the mechanism remains unclear. Recently 33 haemodialysis (HD) patients were exposed to chloramine contamination in the water supply. This led to haemolysis in 24 patients, while nine were unaffected. In the former group haemoglobin decreased from 11.7+/-1.1 to 8.5+/- 1.4 g/dl (P<0.0001) and returned to 11.4+/-0.9 g/dl (P<0.0001) following recovery. During haemolysis, haptoglobin was 38.4+/-10.6 vs 138.1+/-8.3 ng/dl (P<0.0001) following recovery. METHODS: To explore the factors affecting the severity of haemolysis we studied extracellular and intracellular anti-oxidant defence mechanisms 3 months after recovery. In 29 patients and 20 controls we determined plasma glutathione (GSH), and the erythrocyte enzymes glutathione peroxidase (GSH-Px), glutathione reductase (GSH-Rx), and superoxide dismutase (SOD). Serum malondialdehyde (MDA) was measured as a marker of oxidative stress. RESULTS: Plasma GSH was lower in patients as compared to controls (5.49+/-0.26 vs 7.4+/-0.5 micromol/l, P<0.005). There was an inverse correlation between GSH and the degree of haemolysis (r=-0.42, P<0.02). Patients had higher GSH-Rx (4.64+/-0.15 vs 3.97+/-0.12 U/gHb, P<0.02), lower GSH-Px (29. 7+/-1.85 vs 35.5+/-1.62 U/gHb, P<0.001), and similar SOD (0.63+/-0. 02 vs 0.51+/-0.02 U/mgHb) as compared to controls. There was no correlation between the enzyme levels and the degree of haemolysis. MDA was higher in patients (2.37+/-0.07 vs 0.97+/-0.1 nmol/ml, P<0. 0001). There was a correlation between MDA and the years patients were on HD (r=0.43, P<0.02). CONCLUSIONS: These data indicate that HD patients have an impaired anti-oxidant response, which may be attributed in part, to plasma GSH deficiency. Patients with the lowest plasma GSH levels are more susceptible to oxidative stress and consequent haemolysis.
Adult↗
Comparison of hemostatic factors and serum malondialdehyde as predictive factors for cardiovascular disease in hemodialysis patients.
Hemodialysis (HD) patients have accelerated cardiovascular morbidity and mortality rates compared with the general population. Identifying the factors that predict major coronary events in this population can direct the focus on prevention. This cross-sectional study compares known and suspected cardiovascular risk factors in HD patients with and without prevalent cardiovascular disease (CVD). In 76 HD patients (prevalent CVD, 44 of 76 patients), serum lipid, lipoprotein, apolipoprotein (Apo), plasma fibrinogen, tissue plasminogen activator (TPA), plasminogen activator inhibitor (PAI-1), and factor VII levels were measured using standard kits. Serum malondialdehyde (MDA; a marker of oxidative stress) was measured using spectrophotometry. Predictor variables were compared using analysis of variance and chi-squared tests, as appropriate. CVD prevalence was modeled using multiple logistic regression analysis, and odds ratios (OR) were calculated. Serum lipid, lipoprotein, Apo, plasma TPA, PAI-1, and factor VII values did not differ significantly from laboratory norms or discriminate for prevalent CVD in HD patients. Plasma fibrinogen levels were significantly elevated in HD patients compared with laboratory norms (369.4 +/- 130.02 v 276.7 +/- 77.7 mg/dL; P < 0.0001) but were not significantly different in HD patients with and without prevalent CVD. Serum MDA levels, both before and after the midweek HD treatment, were significantly elevated in all HD patients compared with laboratory norms (pretreatment, 2.6 +/- 0.8 nmol/mL; posttreatment, 2.1 +/- 0.3 v 0.91 +/- 0.09 nmol/mL; P < 0.01) and were significantly elevated in HD patients with prevalent CVD versus those without (pretreatment, 2.8 +/- 0.6 v 2.4 +/- 0.4 nmol/mL; P < 0.01; posttreatment, 2.3 +/- 0.4 v 1.94 +/- 0.2 nmol/mL; P < 0.01). Only serum MDA levels, both before and after the midweek treatment, contributed to the explanation of variation in CVD prevalence. OR for CVD in the highest versus lowest tertile of pretreatment MDA level was 2.71 (95% confidence interval [CI], 1.42 to 5.19). ORs for CVD in the highest versus lowest tertile of posttreatment MDA level was 3.65 (95% CI, 1.6 to 8.32).
Adult↗
Alkalinizing local anesthetic does not decrease pain during injection for dorsal penile nerve block.
STUDY OBJECTIVE: To evaluate whether alkalizing local anesthetic with sodium bicarbonate reduces pain related to infiltration of local anesthetic during dorsal penile nerve block for circumcision. DESIGN: Prospective, randomized, double-blind, controlled study. SETTING: E. Wolfson Medical Center, Holon, Israel. PATIENTS: 144 patients aged 15 to 54 years (mean +/- SD = 22.7 +/- 8.8 years), randomized before the block into four groups of 36 patients each. INTERVENTIONS: Group A (control) received a standard solution of 1 mg/kg lidocaine 2% mixed with 0.5 mg/kg bupivacaine 0.5% without epinephrine (pH = 6.3). Patients in Group B, Group C, and Group D received this mixture added with 8.4% sodium bicarbonate for a mean final pH of 6.90, 7.16, and 7.43, respectively. Penile block was performed using a 23-gauge needle by an anesthetist who was blinded to the pH of the solution. MEASUREMENTS AND MAIN RESULTS: Patients were questioned regarding pain suffered during injection of the anesthetic solutions by another physicians who also was blinded to the drug used. Pain was rated by a previously reported subjective pain scale. Mean pain scales were 2.0 +/- 0.17, 2.3 +/- 0.15, 2.2 +/- 0.16, and 1.94 +/- 0.15 for Groups A to D, respectively. The differences between these results were not statistically significant. CONCLUSION: Alkalinizing the acidic local anesthetic solution by sodium bicarbonate does not decrease pain related to infiltration during penile nerve block for circumcision.
Adolescent↗
Serum malondialdehyde and prevalent cardiovascular disease in hemodialysis.
BACKGROUND: Oxidative stress has been proposed as a mechanism by which the accelerated rate of cardiovascular disease (CVD) observed in maintenance hemodialysis (HD) patients may be explained. This study examined the effects of HD and CVD on serum malondialdehyde (MDA) levels as a marker of oxidative stress in HD patients with and without prevalent CVD. Serum MDA levels and CVD prevalence in HD were modeled. METHODS: Serum MDA was determined using spectrophotometry in HD patients (N = 76, 53 men and 23 women, mean age 63.8 years) immediately prior to and at the conclusion of one midweek HD treatment. Traditional CVD risk factors, including serum lipids, lipoproteins, apolipoproteins, and fibrinogen, were also measured, as were serum chemistry and dialysis adequacy. RESULTS: Mean serum MDA levels were significantly elevated in HD patients with prevalent CVD compared with those without, whereas serum lipoprotein and plasma fibrinogen levels did not differ between the two groups. Patients in the highest compared with the lowest tertile of postdialysis MDA were nearly four times as likely to have prevalent CVD, and serum MDA was the single strongest predictor of prevalent CVD in this patient population. CONCLUSIONS: These findings indicate the presence of oxidative stress in HD patients, and are consistent with the theory of oxidative stress as a factor in accelerated CVD in this population.
Aged↗
Patterns of dietary intake and serum lipids interact with proteinuria as risk factors for progression of chronic renal failure.
UNLABELLED: This prospective study assessed the interactions between patterns of nutrient intake and serum lipids with other risk factors for progression of chronic renal failure. The study cohort consisted of 52 individuals with documented chronic renal failure, 18 women and 34 men, with a mean age of 65 +/- 11 years at the time of recruitment. The dependent variable was the rate of progression of chronic renal failure, which was determined by the slope of the curve generated from five or more values of the reciprocal of serum creatinine (SCr-1) and divided by time (in months of follow-up) for each patient, and recorded in dung/month. The independent variables included dietary factors (phosphorus, protein); serum lipids (total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides); proteinuria; serum phosphorus; serum albumin; serum glucose; and blood pressure. Serum creatinine was drawn in a fasting state and determined using the picric acid technique on five or more occasions for each patient. The mean monthly rate of decline in dL/mg/month was calculated for each patient. The cohort was followed for 1.5 years. Descriptive statistics were determined for all variables. Analysis of principal components was used to generate variables representing patterns of nutrient intake and serum lipids. The outcome variable was modeled using stepwise linear regression which included principal components representing dietary and serum lipid patterns. The Student's t test and the F test were used for hypothesis testing. All tests were significant at p < 0.05. RESULTS AND CONCLUSIONS: Multicolinearity prevented the inclusion of more than one individual dietary or serum lipid variable into the multiple linear regression model of rate of decline in kidney function. Principal components representing patterns of dietary intake and serum lipids, contributed to the prediction of rate of decline in renal function together with proteinuria.
Adolescent↗
Regression equation predicts dietary phosphorus intake from estimate of dietary protein intake.
OBJECTIVE: To develop a predictive equation for dietary phosphorus intake. DESIGN: In this clinic-based, cross-sectional study, a dietitian-administered food frequency questionnaire provided dietary intake estimates for a population of patients with chronic renal failure. A prediction equation for dietary phosphorus intake was developed and was validated on another sample of patients with CRF from the same clinic. SUBJECTS: Outpatients treated for chronic renal failure at the E. Wolfson Medical Center Institute of Nephrology in Holon, Israel, participated in the study (N = 104, 73 men and 31 women, mean age = 65.6 years). The validation sample consisted of 53 outpatients with chronic renal failure (38 men and 15 women, mean age = 64.2 years) from the same clinic. MAIN OUTCOME MEASURES: Dietary variables (ie, energy, protein, carbohydrate, fat, phosphorus) were examined in terms of crude intake, as percentage of total energy intake, and per kilogram of body weight. STATISTICAL ANALYSES PERFORMED: Stepwise linear regression analysis and Student's t tests were used to examine relationships between dietary phosphorus and other variables. RESULTS: Dietary phosphorus (milligrams) = 128 + 14 (protein intake [grams]) was the best-fitting equation and explained 84% of the variance in dietary phosphorus intake. APPLICATIONS: The prediction equation for dietary phosphorus intake is especially useful for renal dietitians who calculate patient diets by hand.
Aged↗