Urinary Protein and Enzyme Excretion of Spot Urine in Children with Vesicoureteral Reflux

PURPOSE: The aim of this study was to evaluate the clinical usefulness of measurement of beta2 microglobulin (beta2 MG), N-acetyl-beta-D-glucosaminidase (NAG) of spot urine samples as indices of renal tubular damage and microalbumin of spot urine samples as a parameter of glomerular damage in children with vesicoureteral reflux (VUR) or renal defects. METHODS: We studied 91 children with previous UTI. The children were classified as 62 children without VUR and renal defects (group I), 10 children with VUR, without renal defects (group II), and 19 children with VUR and renal defects (group III). Patients having VUR were separated according to the degree of VUR (mild VUR: VUR grade I-III, severe VUR: VUR grade IV-V). Urinary excretion of beta2 microglobulin (beta2 MG), microalbumin, N-acetyl-beta-D-glucosaminidase (NAG), creatinine were measured in samples of morning urine specimens. Children with VUR or renal defects detected by voiding cystourethrography (VCUG) and DMSA renal scan were investigated. RESULTS: Microalbumin/Cr ratio of spot urine was significantly increased in group III compared group I (42.3+/-27.2 mg/gCr vs 25.2+/-10.9 mg/gCr, P<0.05). NAG/Cr ratio of spot urine was significantly increased in group II compared group I (3.70+/-23.4 mg/gCr vs 18.7+/-12.7 mg/gCr, P<0.05). There was no statistically significant difference of beta2 MG/Cr ratio among three groups. CONCLUSION: Urinary microalbumin excretion of morning urine sample may be a simple and reliable clinical indicators for early identification of renal damage in children with VUR and renal defects. Urinary microalbumin excretion may be useful marker to predict the the severity of VUR.

Urinary Excretion of Various Urinary Proteins in Children with Vesicoureteral Reflux

PURPOSE: This study aimed to examine the excretion of various urinary proteins in children with a history of urinary tract infection(UTI), with or without vesicoureteral reflux(VUR) or reflux nephropathy, and to identify means of predicting the severity of VUR or the presence of reflux nephropathy as indicated by these markers, and to know how these markers are changed after resolution of VUR. METHODS: We studied 30 children with previous UTI, without VUR and renal scarring(group I), 12 children with VUR, without evidence of renal scarring(group II), and 34 children with VUR and renal scarring(group III). 24-hour or 12-hour urine beta2 microglobulin(beta2 MG), microalbumin and N- acetyl-beta-D-glucosaminidase(NAG) were measured in each child. Urinary protein excretions were analyzed according to the degree of VUR(mild VUR : a grade reflux I-III, severe VUR : a grade reflux IV-V). Cases of bilateral VUR were graded by the higher grade of reflux detected. A total of 46 children with primary VUR were followed. Among these patients, VUR was completely resolved in 16 children. Voiding cystourethrography(VCUG) and DMSA scan were performed every year. Values for urinary markers were estimated every year. RESULTS: 24 or 12 hour urine microalbumin and NAG excretions were significantly increased in group III compared to group I(microalbumin : 27.7+/-26.0 mg/gCr vs 15.0+/-10.7 mg/gCr, P<0.05, NAG : 15.2+/-18.7 U/gCr vs 3.4+/-2.2 U/gCr, P<0.05). Urinary beta2 MG excretions were not significantly different between groups. Urinary NAG excretions were elevated in the group of children with severe VUR compared to mild VUR(26.8+/-27.1 U/gCr vs 7.6+/-3.8 U/gCr, P<0.05). After resolution of VUR, urinary microalbumin and NAG excretions were decreased(P<0.05). CONCLUSION: Urinary microalbumin and NAG may be useful clinical indicators to predict the presence of reflux nephropathy and the resolution of VUR. Especially, urinary NAG excretions may be used as a possible method to predict the severity of VUR.

Some Renal Function Indices in Workers Occupationally Exposed to Lead / 대한산업의학회지

The influence of lead exposure on renal function was studied. Three hundred forty two male lead exposed workers who worked in 3 storage battery factories, 5 secondary smelting factories and 3 litharge making factories, and 60 male control workers who were not exposed to lead occupationally were chosen for this study. Blood lead (PbB), zinc protoporphyrin in whole blood (ZPP) and delta-aminolevulinic acid in urine (DALA) were selected as indicators of lead exposure. As indicators of renal function blood urea nitrogen(BUN) , serum creatinine(S-Cr), serum uric acid (S-UA), N-acetyl-beta-D-glucosaminidase in urine (NAG) and urine protein (U-TP) were selected. While the mean values of lead exposure indicators of lead workers were significantly different from non-exposed ones, the mean values of renal function indicators of exposed except S-UA were significantly different from non-exposed. The frequency of workers whose value of renal function indicators were over the nor mal criteria (BUN>20 mg/dl ; S-Cr>1.2 mg/dl ; S-UA>7.0 mg/dl ; NAG>8.0 U/liter; U-TP>8.0 mg/dl) by the level of lead absorption in terms of PbB, ZPP and DALA were calculated. Age adjusted odds ratio of over the normal value of BUN and NAG were statistically significant by the level of ZPP and that of BUN only showed the dose-dependant relationship. But the frequency of over the normal criteria of renal function indicators were not increased by the level of PbB and DALA. On stepwise multiple regression using renal function indicators as a dependent variable and each lead exposure indicator and age as independent variables, only BUN, NAG and U-TP were contributed by the lead exposure indicators. It was found that only NAG of renal function indices was most reliable indicator who showed dose-response relationship with lead exposure and the measurement of NAG for lead workers whose relatively high exposure is highly recommended.

Usefulness of Urinary n-acetyl-beta-d-Glucosaminidase(nag) for a Predictor of Aminoglycoside Nephrotoxicity / 대한신장학회잡지

Nephrotoxicity is a major factor limiting the clinical utility of aminoglycoside antibiotics(AG). In this study, we have therefore investigated the usefulness of the renal tubular protein for a predictor of the nephrotoxicity of AG. We have also compared the nephrotoxicity among different AG. Among the simple fracture patients visiting orthopedics, for whom an AG seemed warrantable, we have sampled thirty-nine subjects--excluding those suffering from severe bleeding, taking drugs, or having renal disease which can affect the renal function. We have set three different groups by the following criteria; ten subjects in group I were given 250mg of Amikacin sulfate twice a day; fifteen subjects in GroupII were given 60mg of Micronomicin sulfate twice a day; and fourteen subjects in GroupIII were given 200mg of Isepacin sulfate twice a day. Urine from each patient was collected for 24 hours before, one week after, and two weeks after the drugs were given, and then the urinary concentrations of NAG, beta2-Microglobulin(beta2-MG), and electrolyte(Na+, K+, Cl-) were measured. The measurement of 24-hour urinary concentrations of NAG shows that, for all three groups, significant increase of the concentrations(P<0.01) is seen between the different times in the same group. The results of measurements of the 24-hour urinary concentrations of beta2-MG, and electrolyte(Na+, Ke+, Cl-) show their increase for all three groups but whithin the normal range. For the samples collected two weeks after the drugs were given, there is a significant decrease in the twenty-four-hour urinary concentrations of NAG(P<0.05) of Group III compared to Group I and II. The resulta of measurements of 24-urinary concentrations of beta2-MG, and electrolyte(Na+, K+, Cl-) show their increase for all three groups but whithin the normal range. In conclusion, we have seen that the nephrotoxicity of the AG appears for all three groups; but, when we compare the nephrotoxicity between the different antibiotics, the nephrotoxicity of Amikacin sulfate and that of Micronomicin sulfate appear stronger than that of Isepacin sulfate. Our data suggest the usefulness of sequential NAG measurements in monitoring and predicting aminoglycoside nephrotoxicity.

Prediction of Steroid Responsiveness in the Primary Nephrotic Syndrome Using Urinary beta2-Microglobulin Level and N-Acetyl-beta-D-Glucosaminidase Activity

PURPOSE: Considering that renal biopsy is not routinely indicated in nephrotic syndrome in children and the risk of the procedure, we studied that it is possible to predict steroid responsiveness in nephrotic syndrome and the difference in responsivenss is related with the histopathologic type using urinary beta2-microglobulin and N-Acetyl-beta-D-Glucosaminidase activity as a safe and noninvasive method. METHODS: We measured serum creatinine, albumin, cholesterol and urinary creatinine, protein, B2M, NAG at the time of admission and after 2 weeks of treatment in 37 cases of primary nephrotic syndrome in children who were admitted to the Pediatric department of Chung-Ang Medical Center between March 1, 1994 and June 30, 1996. RESULTS: The results were as follows : 1) When urinary B2M value of less than 1000microgram/g creatinine was used as the cut-off value, the test identified steroid responsiveness with a sensitivity of 100%, a specificity of 80%. When urinary NAG activity of less than 100U/hr/mg creatinine was used as the cut-off value, the test identified steroid responsiveness with a sensitivity of 100%, a specificity of 81.8%. 2) Pretreatment urinary B2M levels in Good-response and Poor-response group were 559.8+/-718.5microgram/g creatinine, 3599.1+/-4956.7microgram/g creatinine, respectively. There was statistical significance between the two groups (P<0.05). 3) Pretreatment urinary NAG activity in Good-response and Poor-response group were 42.6+/-23.6U/hr/mg creatinine, 79.6+/-80.1U/hr/mg creatinine, respectively. There was statistical significance between the two groups (P<0.05). CONCLUSIONS: In conclusion, measurement of urinary B2M level and NAG activity for early detection of renal tubular damage is helpful in prediction of steroid responsiveness of primary nephrotic syndrome. If the urinary B2M level and NAG activity are elevated, the patient is suspected to steroid resistance. Therefore, prolonged steroid therapy should be avoided in such patients because of their greater chance of not responding. This approach would reduce the many serious side effects of prolonged treatment in patients who are unlikely to benefit.

A Study on Urinary N-acetyl-beta-D-glucosaminidase Activities of Office Workers in a Certain Industrial Complex Area / 예방의학회지

In order to identify the necessary information of biochemical indices for renal effect of lead for the early detection in medical surveillance of lead worker, the reference values of urinary N-acetyl-beta-D-glucosaminidase(NAG) activities were studied with 205 office workers in one industrial complex area who were not exposed to lead occupationally. While study variables selected for lead exposure were blood lead (pbB), blood zinc protoporphyrin(ZPP) and delta-aminolevulinic acid (DALA) in urine, those for renal effect were urinary N-acetyl-beta-D-glucosaminidase(NAG), blood urea nitrogen(BUN), serum creatinine(cr), serum uric acid (Ua), and urinary total protein (U-Tp). The results obtained were as follows: 1. The mean values of blood lead, ZPP and DALA in all subjects were 14.39+/-4.02 microgram/dl, 21.61+/-8.00 microgram/dl, and 2.73+/-0.90 microgram/l respectively. 2. The mean value of urinary NAG activities in all subjects was 3.51+/-2.01 U/l. The mean value of urinary NAG activities, which calculated from NAG activities divided by urinary creatinine concentration (CNAG), was 5.42+/-5.53 U/g creatinine and logarithmic normal distributed. 3. The reference value of urinary NAG activity was 12.06 U/g creatinine (95% CI=10.57-14.76U/g creatinine). 4. Logarithmic CNAG(r=0.781 P<0.01), U-TP(r=0.670 p<0.01) and ZPP (r=0.172 p<0.05)showed statistically significant correlation with CNAG.