Biomedical subjects

W S Yang

Publications and source records attributed to W S Yang.

75 records · Page 5Linked to original sources

PubMedDate not supplied

Reduced oxidative stress in hypoalbuminemic CAPD patients.

OBJECTIVE: Albumin is one of the plasma antioxidants. The higher incidence of cardiovascular disease in dialysis patients with hypoalbuminemia may be related to decreased antioxidant capacity resulting from low serum albumin. We evaluated malondialdehyde (MDA), a marker of oxidative stress, and total antioxidant capacity (TAC) in relation to serum albumin in continuous ambulatory peritoneal dialysis (CAPD) patients. PATIENTS AND METHODS: In this cross-sectional study, we measured MDA, TAC, albumin, uric acid (another important plasma antioxidant), prealbumin, and C-reactive protein (CRP) in the blood of 66 CAPD patients and 30 normal controls.Twenty-two CAPD patients with albumin less than or equal to 3.5 g/dL were divided into two groups: In the experimental group (n = 11), MDA,TAC, and CRP were measured before and after repeated infusion of 20% albumin 100 mL daily for 7 days. In the control group (n = 11), the same parameters were measured without albumin infusion. RESULTS: CAPD patients had lower albumin and higher MDA,TAC, and uric acid than normal controls. There were positive correlations between albumin and TAC or uric acid in CAPD patients. Contrary to our expectation, there was also positive correlation between albumin and MDA in CAPD patients (r = 0.37, p = 0.004). MDA showed a positive correlation with TAC. Uric acid was correlated with TAC. It did not, however, show correlation with MDA. Log CRP was negatively correlated with albumin, but did not show correlation with MDA or TAC. Prealbumin was correlated with MDA, TAC, albumin, and uric acid. Serum albumin in the experimental group increased from 2.5+/-0.3 g/dL to 3.6+/-0.2 g/dL (p < 0.001) at the end of repeated infusions. No changes were seen in MDA, TAC, and CRP in either group. CONCLUSIONS: The present study suggests that lipid peroxidation is increased in CAPD patients and that this is not due to weakening of antioxidant defenses of plasma. Increased TAC was mainly caused by a higher level of uric acid. Reduced, rather than increased, MDA in hypoalbuminemic patients and lack of effects of albumin infusion on levels of MDA suggest that the frequent occurrence of cardiovascular disease in dialysis patients with hypoalbuminemia is not due to the decrease in antioxidant capacity resulting from low serum albumin.

Adult↗

PubMedDate not supplied

Fibrinogen and fibrinolytic activity in CAPD patients with atherosclerosis and its correlation with serum albumin.

OBJECTIVE: It has been suggested that hypoalbuminemia in dialysis patients leads to a hypercoagulable state, however, the relationship between serum albumin and fibrinogen or fibrinolytic activity has not been well-documented. The aim of this study was to investigate the changes of fibrinogen, tissue plasminogen activator (tPA), plasminogen activator inhibitor type-1 (PAI-1), and lipid levels in continuous ambulatory peritoneal dialysis (CAPD) patients with atherosclerosis, and the relationship between those factors and serum albumin. DESIGN: A cross-sectional study. SETTING: A university hospital. PATIENTS: Twenty CAPD patients with atherosclerosis, 49 CAPD patients without atherosclerosis, and 33 normal controls were included. Presence of atherosclerosis was determined by positive results in a stress thallium single-photon emission computed tomography or an ankle brachial index less than 0.9. Coronary angiography and/or Doppler ultrasound of extremities were followed for the patients with positive results to confirm atherosclerotic cardiovascular disease. MAIN OUTCOME MEASURES: tPA and PAI-1 levels were determined with ELISA method, and fibrinogen with thrombin time method. Serum albumin and lipids were also measured. RESULTS: Serum albumin and HDL-cholesterol levels were significantly lower, and the ratio of total cholesterol/HDL was significantly higher, in CAPD patients than in normal controls. CAPD patients with atherosclerosis had significantly higher fibrinogen, tPA, and PAI-1 levels than other groups: tPA was an independent predictor of atherosclerotic vascular disease in CAPD patients in stepwise logistic regression analysis. Serum albumin level was inversely correlated with fibrinogen (r = -0.28; p < 0.05) in CAPD patients, but not with tPA or PAI-1 levels. PAI-1 level was correlated with tPA (r = 0.37; p < 0.01) and triglycerides (r = 0.32; p < 0.05). CONCLUSIONS: Association of high levels of fibrinogen and PAI-1 with lipid disorders may be of importance in the development of atherosclerosis in CAPD patients. Hypoalbuminemia may contribute to atherosclerosis via increased synthesis of fibrinogen.

Adult↗

PubMedDate not supplied

Lipoprotein(a) and apolipoprotein(a) phenotypes in patients with end-stage renal disease.

OBJECTIVE: To evaluate the distribution pattern of apolipoprotein(a) [Apo(a)] phenotypes in Koreans and the effect of dialysis modality on serum lipoprotein(a) [Lp(a)] concentration according to apo(a) phenotype in patients with end-stage renal disease (ESRD). DESIGN: Cross-sectional study. SETTING: A university hospital. PARTICIPANTS: 153 normal controls, 99 hemodialysis (HD) patients and 82 continuous ambulatory peritoneal dialysis (CAPD) patients. MAIN OUTCOME MEASURES: Fasting serum Lp(a), lipids, and apo(a) phenotypes were measured. RESULTS: The frequencies of the subjects with apo(a) phenotypes of high-molecular weight only, including S3, S4, or S5 or null type were 95.4% of control, 100% of HD patients, and 95.1% of CAPD patients. The frequent apo(a) phenotypes in Koreans consisted of S4, S4S5, S5, and S5S5 isoforms. Significant difference was found in serum Lp(a) concentration among controls and HD and CAPD patients [median (Interquartile range): 0.05 g/L, (0.01-0.19); 0.19 g/L, (0.10-0.35); 0.63 g/L, (0.28-0.90), p < 0.001]. Lp(a) levels in CAPD patients were significantly higher than in HD patients for all four common apo(a) isoforms found in Korean subjects. CAPD patients had higher total and LDL cholesterol levels, and higher ApoB levels than HD patients. Significant differences were found in serum albumin levels between controls and HD and CAPD patients (44 +/- 3 g/L, 40 +/- 4 g/L, 32 +/- 7 g/L, respectively, p < 0.05). There were significant inverse correlations between serum albumin and Lp(a) (r = -0.33, p < 0.01), total cholesterol (r = -0.31, p < 0.01), LDL (r = -0.39, p < 0.01) or ApoB (r = -0.35, p < 0.01) in ESRD patients. A significant positive correlation was found between serum albumin and ApoA1 (r = 0.24, p < 0.01). CONCLUSION: These findings indicate that Koreans have mainly high molecular weight apo(a) phenotypes and serum Lp(a) is elevated in CAPD patients compared to HD patients for common apo(a) phenotypes, which may contribute to the frequent cardiovascular mortality in CAPD patients.

Adult↗