Clinical significance of fractional magnesium excretion (FEMg) as a predictor of interstitial nephropathy and its correlation with conventional parameters.

BACKGROUND: Elevated urine Mg excretion and its correlation with histological damage in tubulo-interstitial nephropathy (TIN) were reported. Here we investigated the clinical significance of the fractional excretion of Mg (FEMg) for the prediction of TIN. METHODS: We enrolled and assessed 94 adult patients with various renal diseases diagnosed principally by renal biopsy. RESULTS: Our stratified analysis based on the value of the conventional TIN parameter N-acetylglucosaminidase (NAG) excretion showed that the high-NAG index group (more than median value of NAG-to-Cr ratio, n = 47) demonstrated significantly high FEMg values (p = 0.017). A univariate analysis revealed a significant correlation between the FEMg and the NAG index (R = 0.60) but not for other parameters. A multivariate regression analysis confirmed the significance of the FEMg as an effective predictor of the NAG index. The FEMg showed a significant correlation with the estimated glomerular filtration rate (eGFR) in the patients with eGFR ≤ 30 mL/min. The correlation of FEMg with the NAG index was not observed in the primary glomerulonephritis patients but was apparent in the patients with hypertensive nephrosclerosis or interstitial nephritis. CONCLUSION: Our findings may indicate that the combination of the FEMg and the NAG index can provide a specific, sensitive assessment for TIN in patients without renal insufficiency.

Dialysate purification after introduction of automated hot water disinfection system to central dialysis fluid delivery system.

Most dialysis clinics in Japan have mainly adopted the central dialysis fluid delivery system (CDDS) to provide constant treatment to many patients. Chemical disinfection is the major maintenance method of the CDDS. Our clinic introduced an automated hot water disinfection system that used the heat conduction effect to disinfect a reverse osmosis (RO) device and dialysis fluid supply equipment. Endotoxin level and the amount of viable bacteria often showed abnormal values before introduction of this system. After its introduction, weekly disinfection resulted in endotoxin levels and the amount of viable bacteria lower than measurement sensitivity. In hot water disinfection, water heated to 90°C in the RO tank flows into the dialysis fluid supply equipment. The maximum temperature inside the tank of the supply equipment is 86.3°C. (We confirmed that the temperature was maintained at 80°C or more for 10 minutes or more during the monitoring.) Dialysate purification was maintained even after introduction of the automated hot water disinfection system and the dialysate could be supplied stably by the CDDS. Therefore, this disinfection system might be very useful in terms of both cost and safety, and can be used for dialysis treatment of multiple patients.

Contribution of residual renal function on peritoneal solute transport in dialysis patients.

BACKGROUND: Increased peritoneal solute transport rate (PSTR) is primarily a consequence of continuous exposure to bioincompatible glucose-based peritoneal dialysis (PD) solutions. However, relationships between increasing PSTR and dialysate glucose load remain unclear. As some PD patients with preserved residual renal function do not show increased PSTR despite long-term PD, we examined whether loss of residual renal function is associated with increased PSTR on long-term PD. METHODS: We evaluated 35 patients who started PD between 1997 and 2002 and received continuous PD treatment for >6 years. Data included baseline clinical data, residual renal function, urea and creatinine clearance, dialysate glucose load, ultrafiltration, and the use of icodextrin and renin-angiotensin system inhibitors. Peritoneal equilibration test results and data were collected annually for 6 years. RESULTS: Both the glomerular filtration rate and urine volume at 6 years on PD showed significant negative correlations with the dialysate-to-plasma creatinine ratio (D/P Cr) at 6 years (r = -0.716 and r = -0.717, respectively). Multivariate analysis showed only urine volume at 6 years on PD as an independent covariate of the D/P Cr at 6 years on PD. CONCLUSIONS: Loss of residual renal function is directly associated with increased PSTR in patients on long-term PD.