Gyeong A Kim

Plasma brain natriuretic peptide concentration on assessment of hydration status in hemodialysis patient

BACKGROUND Brain natriuretic peptide (BNP) is released into circulation in response to ventricular dilatation and pressure overload. Plasma BNP concentration correlates with left ventricular mass and dysfunction, which is prevalent in hemodialysis (HD) patients. METHODS To evaluate the potential of BNP level for determination of hydration status, we measured inferior vena caval diameter (IVCD) and BNP levels and performed bioimpedance analysis in 49 HD patients. RESULTS Pre-HD BNP levels remained unchanged after HD. Agreement between IVCD and pre-HD BNP level in overhydration was significant (kappa = 0.304). The area under the receiver operating characteristic (ROC) curve for overhydration was 0.819 for pre-HD BNP level. When extracellular fluid/total-body water (ECF/TBW) ratios of HD patients were compared with those of 723 controls, pre- and post-HD BNP levels were significantly greater in overhydrated patients. The area under the ROC curve for overhydration by ECF/TBW ratio was 0.781 for pre-HD BNP level. However, there was no significance for pre- or post-HD BNP levels on assessment of normohydration or underhydration. Pre-HD BNP level correlated significantly with post-HD BNP level, post-HD diastolic blood pressure, pulse pressure, and ECF/TBW ratio. IVCD correlated significantly with post-HD BNP level. CONCLUSION BNP level seems to have a limited potential for assessment of overhydration in HD patients.

Evidence for heme oxygenase-1 association with caveolin-1 and -2 in mouse mesangial cells

The interaction of heme oxygenase‐1 (HO‐1) and caveolin in the cultured mouse mesangial cells (MMC) was investigated. In normal MMCs, high levels of caveolin‐2 and low level of caveolin‐1 at mRNA and protein level were observed without any detectable expression of caveolin‐3. Upon treating the MMCs either with cadmium (Cd) or spermine NONOate (SPER/NO), expression of HO‐1 mRNA and protein was increased. Caveolae rich membranous fractions from the MMCs treated with Cd or SPER/NO contained both HO‐1 and caveolin‐1 or caveolin‐2. The experiments of immuno‐precipitation showed complex formation between the HO‐1 and caveolin‐1 or caveolin‐2 in the Cd treated MMCs. Confocal microscopic results also support co‐localization of HO‐1 and caveolin‐1 or caveolin‐2 at the plasma membrane. Co‐localization of caveolins with HO‐1 in caveolae suggested that caveolin could also play an important role in regulating the function of HO‐1. IUBMB Life, 55: 525‐532, 2003

Optimization of dialysate sodium in sodium profiling haemodialysis

SUMMARY:  Sodium profiling haemodialysis is a modified method of sodium gradient dialysis during which dialysate sodium follows a time‐dependent profile. Sodium profiling haemodialysis has claimed to reduce intradialytic discomforts such as hypotension, muscle cramps, and disequilibrium syndrome. Having the low sodium period is an essential part of the sodium profiling haemodialysis to compensate for the sodium gain during the high sodium period. In spite of this, however, the incidence of interdialytic complications that results from the excessive sodium gain has been reported in previous literature. Making the prediction of optimal dialysate sodium concentration for isonatric dialysis is practically very difficult since too many variables influence the sodium gradient, including the initial plasma sodium and tonicity and/or dialysis dynamics that differ from patient to patient and from treatment to treatment. As for sodium profiling haemodialysis, complexities are added further since details of profile, such as type and form of profile, or initial, terminal, or time‐distribution of dialysate sodium are varied considerably. We have recently reported that the intradialytic sodium balance and interdialytic weight gain are directly related to the time‐averaged concentration of dialysate sodium (TACNa). The dialysate sodium can be optimized using this concept of TACNa for sodium profiling dialysis. TACNa should be approximately 0.5–0.8 mmol/L lower than patients predialysis serum sodium concentrations to achieve a sodium balance neutral dialysis. In that study the optimal TACNa, seems to be between 137.8 and 143.5 mmol/L. Such an optimal value should be defined for the individual centres based on their profile protocols for clinical use. In the future, dialysate sodium should be optimized based on the exact prediction of the postdialysis plasma sodium levels.

Development of Anthropometry-Based Equations for the Estimation of the Total Body Water in Koreans

For developing race-specific anthropometry-based total body water (TBW) equations, we measured TBW using bioelectrical impedance analysis (TBWBIA) in 2,943 healthy Korean adults. Among them, 2,223 were used as a reference group. Two equations (TBWK1 and TBWK2) were developed based on age, sex, height, and body weight. The adjusted R2 was 0.908 for TBWK1 and 0.910 for TBWK2. The remaining 720 subjects were used for the validation of our results. Watson (TBWW) and Hume-Weyers (TBWH) formulas were also used. In men, TBWBIA showed the highest correlation with TBWH, followed by TBWK1, TBWK2 and TBWW. TBWK1 and TBWK2 showed the lower root mean square errors (RMSE) and mean prediction errors (ME) than TBWW and TBWH. On the Bland-Altman plot, the correlations between the differences and means were smaller for TBWK2 than for TBWK1. On the contrary, TBWBIA showed the highest correlation with TBWW, followed by TBWK2, TBWK1, and TBWH in females. RMSE was smallest in TBWW, followed by TBWK2, TBWK1 and TBWH. ME was closest to zero for TBWK2, followed by TBWK1, TBWW and TBWH. The correlation coefficients between the means and differences were highest in TBWW, and lowest in TBWK2. In conclusion, TBWK2 provides better accuracy with a smaller bias than the TBWW or TBWH in males. TBWK2 shows a similar accuracy, but with a smaller bias than TBWW in females.