The influence of hemodialysis membrane permeability on serum paraoxonase-1 activity and oxidative status parameters.

We aimed to measure oxidative stress parameters and paraoxonase-1 (PON-1) enzyme activities in chronic hemodialysis (HD) patients and to investigate whether HD membrane permeability has any influence on those measures. Forty-seven HD patients and 24 controls were enrolled. At the first step of the study, all HD patients had undergone HD treatment via "low-flux" membranes for 4 weeks. At the second step of the study, the membranes were switched to "high-flux" membranes and HD treatments were also performed via "high-flux" membranes for 4 weeks. Blood samples were withdrawn after completion of 4 weeks treatment for each membrane. Total oxidant status (TOS), total antioxidant status (TAS), and paraoxonase and arylesterase activities were measured in blood samples of the patients and the controls. TOS and oxidative stress index (OSI) of both membranes were higher than controls (all, P < 0.05), while TAS and paraoxonase and arylesterase activities were lower (all P < 0.05). Paraoxonase (P < 0.05, r = -0.437 and P < 0.05, r = -0.453, respectively) and arylesterase (P < 0.05, r = -0.333 and P < 0.05, r = -0.371, respectively) activities of "low-flux" and "high-flux" membranes were inversely correlated with OSI. There were no significant differences between "low-flux" and "high-flux" membranes in regard to oxidative stress parameters or PON-1 enzyme activities (all, P > 0.05). HD patients have increased oxidative stress and decreased serum PON-1 activities inversely correlated with oxidative stress. Membrane permeability seems to have no influence on oxidative stress parameters and PON-1 enzyme activities.

Serum stem cell factor level in renal transplant recipients with posttransplant erythrocytosis.

The etiology of posttransplant erythrocytosis (PTE) remains unclear, and the most frequently suggested causative factors are still a matter of controversy. We aimed to investigate serum-soluble stem cell factor (sSCF) along with serum erythropoietin (EPO) levels in renal transplant recipients (RTRs) with PTE. Thirteen RTRs with PTE, 42 RTRs without PTE, and 42 healthy controls were included. Serum sSCF and EPO levels were determined using an enzyme-linked immunosorbent assay kit. Expected and observed/expected EPO levels were calculated. Serum sSCF levels and observed/expected EPO were significantly higher in RTRs with PTE than both RTRs without PTE and controls. In RTRs with PTE, sSCF level was significantly correlated with hematocrit and observed/expected EPO, respectively. Significant correlation was also observed between hematocrit level and observed/expected EPO in RTRs with PTE. Increased sSCF level and inadequate suppression of EPO production seem to have a role in the pathogenesis of PTE.

The prevalance, epidemiology and risk factors for onychomycosis in hemodialysis patients.

BACKGROUND: Onychomycosis has a high prevalance among immunocompromised patients such as diabetics and hemodialysis patients. In the present study, we aimed to investigate the prevalence of onychomycosis among hemodialysis patients with and without diabetes mellitus, and to find out the factors likely to be associated with the development of onychomycosis among hemodialysis patients. METHODS: One hundred and nine hemodialysis patients were enrolled. Fifty-seven of hemodialysis patients had the diagnosis of diabetes mellitus. Nail scrapings were obtained from 76 patients who had dystrophic nail changes. Samples were examined with 20% potassium hydroxide solution and all of the samples were inoculated on Saboraud's dextrose agar, potateus dextrose agar and mycobiotic agar. Diagnosis of onychomycosis was based on the presence of both positive clinical signs and positive potassium hydroxide test. RESULTS: Onychomycosis was diagnosed in 26.6% of hemodialysis patients. Diabetes mellitus was present in 68.9% of patients with onychomycosis. Toenail scraping cultures were reported to be positive in 19.7% of patients with dystrophic nail changes. Logistic regression analysis revealed that the presence of diabetes mellitus and the mean duration of hemodialysis were the significant predictors associated with the development of onychomycosis. CONCLUSION: The prevalence of dystrophic nail changes and onychomycosis is increased among hemodialysis patients. The dialysis duration and the presence of diabetes mellitus are the independent risk factors associated with the development of onychomycosis in uraemic patients.

Increased incidence of carotid artery wall changes and associated variables in hemodialysis patients without symptomatic cardiovascular disease.

Cardiovascular disease (CVD) is still the major cause of the morbidity and mortality in hemodialysis (HD) patients. The characteristics of major arterial changes, atherosclerosis and related risk factors in HD patients remain unclear. We aimed to evaluate the atherosclerotic process in asymptomatic HD patients and healthy volunteers, and to determine the association between the risk factor(s) and the atherosclerotic process in these groups. 92 HD patients (female: 43, male: 49) and 62 age and sex matched healthy volunteers (female: 27, male: 35) were enrolled in this study. Diabetics, smokers, and patients with symptomatic CVD were excluded. The right and left carotid intima-media thicknesses (CIMTs) were measured and plaque structures were studied by B-mode ultrasound. The mean CIMT in patients and control group were 0.79 +/- 0.16 mm and 0.54 +/- 0.09 mm, respectively. Mean CIMT in HD patients was thicker (p < 0.001) and the presence ratio of plaque was higher in patients group (n=38, %61.2 vs n=9, %17.3) (p < 0.001). Calcified type of plaque was more frequent in HD patients than control group. Age (r=0.48, p < 0.001), left ventricular mass (r=0.42, p < 0.05), and homocysteine (r=0.46, p < 0.01), mean hematocrit (r=-0.36, p < 0.05), plasma CRP (r=0.50, p < 0.001), ESR (r=0.43, p < 0.01) and albumin (r= -0.34, p < 0.05) levels were correlated with the CIMT measurements and plaque presence, significantly. -CIMT as an atherosclerotic process indicator is thicker in asymptomatic HD patients than healthy subjects. We concluded that in addition to various classical risk factors, uremic environment may also contribute to acceleration of the atherosclerotic process.

The influence of hemodialysis on P-wave signal-averaged electrocardiogram findings.

The role of P-wave signal-averaged electrocardiography (P-SAECG) in the prediction of atrial fibrillation (AF) attacks has been validated in various disease states. In the present study, we aimed to investigate the effect of hemodialysis (HD) on P-SAECG parameters and to determine the related risk factors that might affect those parameters. Ninety-one HD patients and 68 controls were included. Hemoglobin levels, serum electrolytes, arterial pH, and interdialytic weight changes were assessed. P-wave duration (PWD) and late potentials of P wave (root-mean-square voltage for the last 20 ms of the signal-averaged P wave [LP20]) were determined by P-SAECG. Pre- and postdialysis PWDs were significantly increased in HD patients than in controls (both P < 0.05), while the voltages of pre- and postdialysis LP20 were significantly reduced (both P < 0.05). A significant increase in PWD (P < 0.05) and a significant decrease in LP20 (P < 0.05) were observed following HD. Pre- and postdialysis PWDs and LP20 were correlated with age (all P < 0.05), dialysis duration (all P < 0.05), and left atrial diameters (LADs) (pre- and postdialysis) (all P < 0.05). Intradialytic changes in serum potassium levels were only correlated with postdialysis PWD and LP20 in HD patients (both P < 0.05). HD seems to increase PWD and to reduce LP20. Advanced age, duration of HD, intradialytic change in serum potassium levels, and LAD seem to be the important associates of P-SAECG parameters in HD patients.

Haemodialysis hypotension and nitric oxide production: comparison of heparin with parnaparin.

BACKGROUND: There is increasing evidence for the role of nitric oxide (NO) in haemodialysis hypotension but the source of elevated NO is still controversial. Heparin has been reported to enhance NO production by cultured human endothelial cells. The aim of this study was to compare the role of unfractionated heparin and low molecular weight heparin (LMWH, parnaparin) on mean arterial pressure (MAP) and NO production in haemodialysis patients with hypotensive episodes. PATIENTS AND METHODS: Ten maintenance haemodialysis patients with hypotensive episodes were involved in this study. Patients were anticoagulated with heparin for 3 weeks and then switched to parnaparin for 3 weeks. Serum NO levels were analysed before starting dialysis, at the nadir of MAP during a haemodialysis session and at the end of dialysis in the last haemodialysis session of the 3rd week of each anticoagulation treatment. RESULTS: NO levels were 39.4 +/- 13.2 microM at the beginning of haemodialysis, 92.4 +/- 31.4 microM during hypotensive episode and 43.1 +/- 25.1 microM at the end of dialysis with heparin treatment (p < 0.05). In the parnaparin period, NO levels were 47.2 +/- 22.7 microM at the beginning, 80.7 +/- 46.5 microM during the hypotensive episode and 45.8 +/- 23.2 microM at the end of the session (p < 0.05). The percent increase in NO levels during the hypotensive period compared to that at the beginning of haemodialysis with heparin was significantly higher than that with parnaparin (140.2 +/- 50.4 vs. 119.6 +/- 44.8%; p < 0.05). The percent decrease in MAP with heparin use was also significantly higher than with parnaparin use (48.6 +/- 6.4 vs. 39.6 +/- 5.3%; p < 0.05). CONCLUSION: We have observed that MAP decrements and NO increases were less manifest during hypotensive episodes with parnaparin treatment compared to heparin. This difference may be related to differences in endothelial binding capacity, thrombin affinity and/or effects on platelet functions of unfractionated heparin and LMWHs.