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OBJECTIVE To determine if plasma concentrations of symmetric dimethylarginine (SDMA), N-acetyl-beta-d-glucosaminidase (NAG), GGT, ALT, AST, lactate, total calcium, and ionized calcium (iCa) and the calcium:phosphorus ratio are clinically relevant biomarkers to detect early stages of tubular lesions in snakes. ANIMALS 6 adult corn snakes (Pantherophis guttatus). METHODS Corn snakes were administered 11 injections of gentamicin at 50 mg/kg, SC, q 24 h in an experimental model of induced tubular necrosis. Plasma biochemistry and blood gas analyses were performed at baseline and after the 3rd and 11th injections. Parameters were compared between time points using a paired Wilcoxon test. In 3 individuals, renal biopsies were collected at baseline before starting injections and at the 3rd and 11th injections, while renal tissue samples were procured after euthanasia in all individuals. RESULTS Renal proximal and distal tubular necrosis and hepatic steatosis were present in all individuals at necropsy. Compared to baseline, decreased blood concentrations of lactate, ionized calcium, and total calcium and a decreased calcium:phosphorus ratio were noted. A significant decrease of lactate and ionized calcium was observed after 3 days. Conversely, no changes in SDMA, NAG, ALT, AST, GGT, and sodium were detected. CLINICAL RELEVANCE Ionized calcium and lactate concentrations were the earliest parameters to decrease compared to baseline values in this experimental model. While SDMA is a sensitive indicator of renal disease in mammals, this biomarker did not increase in a model of induced acute tubular necrosis in corn snakes. [ABSTRACT FROM AUTHOR]

Acute and chronic kidney diseases are an evolving continuum for which reliable biomarkers of early disease are lacking. The potential use of glycosidases, enzymes involved in carbohydrate metabolism, in kidney disease detection has been under investigation since the 1960s. N-acetyl-beta-D-glucosaminidase (NAG) is a glycosidase commonly found in proximal tubule epithelial cells (PTECs). Due to its large molecular weight, plasma-soluble NAG cannot pass the glomerular filtration barrier; thus, increased urinary concentration of NAG (uNAG) may suggest injury to the proximal tubule. As the PTECs are the workhorses of the kidney that perform much of the filtration and reabsorption, they are a common starting point in acute and chronic kidney disease. NAG has previously been researched, and it is widely used as a valuable biomarker in both acute and chronic kidney disease, as well as in patients suffering from diabetes mellitus, heart failure, and other chronic diseases leading to kidney failure. Here, we present an overview of the research pertaining to uNAG's biomarker potential across the spectrum of kidney disease, with an additional emphasis on environmental nephrotoxic substance exposure. In spite of a large body of evidence strongly suggesting connections between uNAG levels and multiple kidney pathologies, focused clinical validation tests and knowledge on underlining molecular mechanisms are largely lacking. [ABSTRACT FROM AUTHOR]

Acute and chronic kidney diseases are an evolving continuum for which reliable biomarkers of early disease are lacking. The potential use of glycosidases, enzymes involved in carbohydrate metabolism, in kidney disease detection has been under investigation since the 1960s. N-acetyl-beta-D-glucosaminidase (NAG) is a glycosidase commonly found in proximal tubule epithelial cells (PTECs). Due to its large molecular weight, plasma-soluble NAG cannot pass the glomerular filtration barrier; thus, increased urinary concentration of NAG (uNAG) may suggest injury to the proximal tubule. As the PTECs are the workhorses of the kidney that perform much of the filtration and reabsorption, they are a common starting point in acute and chronic kidney disease. NAG has previously been researched, and it is widely used as a valuable biomarker in both acute and chronic kidney disease, as well as in patients suffering from diabetes mellitus, heart failure, and other chronic diseases leading to kidney failure. Here, we present an overview of the research pertaining to uNAG’s biomarker potential across the spectrum of kidney disease, with an additional emphasis on environmental nephrotoxic substance exposure. In spite of a large body of evidence strongly suggesting connections between uNAG levels and multiple kidney pathologies, focused clinical validation tests and knowledge on underlining molecular mechanisms are largely lacking.

In 2011, phthalates, mainly di-(2-ethylhexyl) phthalate (DEHP), were found to have been added to a variety of foods in Taiwan, increasing the risk of microalbuminuria in children. Exposure to melamine perhaps modifies that risk. This prospective cohort study investigates whether renal injury resulting from exposure to DEHP-tainted foods from the 2011 Taiwan Food Scandal is reversed over time. The temporal and interactive effects of past daily DEHP intake, current daily DEHP intake, and urinary melamine levels on oxidative stress and renal injury were also examined.Two hundred possibly DEHP-affected children (aged 50 μg/kg/day). Urinary melamine levels were found to correlate significantly with both urinary ACR and oxidative stress markers. The highest impact associated with exposure to DEHP-tainted foods in increasing urinary ACR of children was observed during the first wave, and the effect may partially diminish over time. These results suggest that continuous monitoring of renal health and other long-term health consequences is required in individuals who were affected by the scandal in 2011.

Diabetes mellitus (DM) is known to be one of the most common causes of end-stage renal disease. The disease is usually not detected on time, because of the large functioning reserve of the kidney. Currently used markers (serum creatinine, creatinine clearance, urea, and electrolytes) remain relatively normal even when more than 50% of the renal nephron is not functioning. The aim of this study was to determine the level of urinary N-acetyl-beta-d-glucosaminidase (NAG) in diabetic adults in comparison with some currently used markers. A total of 56 diabetic patients between the ages of 23 and 63 were used for this study and 30 nondiabetic between the ages of 18 and 62 were used as control. The diabetic patients were classified into three groups based on how long they have been diagnosed: 5 years (25). Spot midstream urine samples were collected into sterile containers, and blood samples were collected into plain tubes. All the analyses were done spectrophotometrically. Creatinine clearance was calculated using the Cockcroft–Gault Equation. There was a significant increase (P < 0.01) in NAG values of 2–5 years and above 5 years and control. The urinary microalbumin concentration of controls was significantly different (P < 0.05) only with those who have had DM for

Objective: To determine if plasma concentrations of symmetric dimethylarginine (SDMA), N-acetyl-beta-d-glucosaminidase (NAG), GGT, ALT, AST, lactate, total calcium, and ionized calcium (iCa) and the calcium:phosphorus ratio are clinically relevant biomarkers to detect early stages of tubular lesions in snakes., Animals: 6 adult corn snakes (Pantherophis guttatus)., Methods: Corn snakes were administered 11 injections of gentamicin at 50 mg/kg, SC, q 24 h in an experimental model of induced tubular necrosis. Plasma biochemistry and blood gas analyses were performed at baseline and after the 3rd and 11th injections. Parameters were compared between time points using a paired Wilcoxon test. In 3 individuals, renal biopsies were collected at baseline before starting injections and at the 3rd and 11th injections, while renal tissue samples were procured after euthanasia in all individuals., Results: Renal proximal and distal tubular necrosis and hepatic steatosis were present in all individuals at necropsy. Compared to baseline, decreased blood concentrations of lactate, ionized calcium, and total calcium and a decreased calcium:phosphorus ratio were noted. A significant decrease of lactate and ionized calcium was observed after 3 days. Conversely, no changes in SDMA, NAG, ALT, AST, GGT, and sodium were detected., Clinical Relevance: Ionized calcium and lactate concentrations were the earliest parameters to decrease compared to baseline values in this experimental model. While SDMA is a sensitive indicator of renal disease in mammals, this biomarker did not increase in a model of induced acute tubular necrosis in corn snakes.

Detection of equine acute kidney injury (AKI) is hindered by limited markers of early renal damage in horses. N-acetyl-β-D-glucosaminidase (NAG), a lysosomal enzyme in renal tubular epithelium released into urine during tubular insult, has shown promise for early identification of AKI in humans and other species. We validated an assay for NAG in equine urine and measured urinary NAG in 7 azotemic and 7 non-azotemic client-owned adult horses. The enzymatic NAG assay was validated using within- and between-run coefficients of variation (CVs), recovery following standard addition, and linearity of dilution. Intra- and inter-run CVs (21% and 3.2%, respectively), average recovery following standard addition (99–109%), and linearity under serial dilution (R 2 = 0.997) were satisfactory. Urine NAG index was significantly correlated with urinary fractional excretion of sodium (FENa; ρ = 0.76, p < 0.001) and plasma creatinine (ρ = 0.74, p = 0.001). Median urine NAG indices were higher in azotemic horses (p = 0.006), in horses with increased urinary FENa (p = 0.006), and in horses with increased urine gamma-glutamyl transferase index (p = 0.032). Urine NAG can be measured in horses and shows positive correlation with 2 current renal biomarkers. Additional work is needed to establish normal equine reference intervals and characterize the increase of urine NAG index in horses in relation to tubular injury. [ABSTRACT FROM AUTHOR]

Diabetes mellitus (DM) is known to be one of the most common causes of end-stage renal disease. The disease is usually not detected on time, because of the large functioning reserve of the kidney. Currently used markers (serum creatinine, creatinine clearance, urea, and electrolytes) remain relatively normal even when more than 50% of the renal nephron is not functioning. The aim of this study was to determine the level of urinary N-acetyl-beta-d-glucosaminidase (NAG) in diabetic adults in comparison with some currently used markers. A total of 56 diabetic patients between the ages of 23 and 63 were used for this study and 30 nondiabetic between the ages of 18 and 62 were used as control. The diabetic patients were classified into three groups based on how long they have been diagnosed: <2 years (25), 2-5 years (30), and >5 years (25). Spot midstream urine samples were collected into sterile containers, and blood samples were collected into plain tubes. All the analyses were done spectrophotometrically. Creatinine clearance was calculated using the Cockcroft-Gault Equation. There was a significant increase (P < 0.01) in NAG values of 2-5 years and above 5 years and control. The urinary microalbumin concentration of controls was significantly different (P < 0.05) only with those who have had DM for <2 years. Urinary creatinine concentration of control was significantly higher (P < 0.05) than values of all the diabetic groups. There was a significant increase (P < 0.01) in creatinine clearance of control group and those who have had DM for <2 years. It is thus concluded that urinary NAG can be used as an early marker in the diagnosis of diabetic nephropathy since urinary NAG increases first before the other markers analyzed in this current study begins to increase. [ABSTRACT FROM AUTHOR]

PEG-400 modified sulfur quantum dots were used to detect the activity of N-acetyl-beta-D-glucosaminidase based on the fluorescence inner filter effect. [Display omitted] • Fluorescent sensor platform for detecting NAG was designed based on IFE. • The platform had high sensitivity and low limit of detection for NAG (0.1 U L−1). • The NAG detection fluorescent sensor platform was applied to bovine serum samples. N-acetyl-beta-D-glucosaminidase (NAG) is an important biomarker for early clinical diagnosis of renal disease, suggesting the necessity to develop a fast and sensitive method for its detection. In this paper, we developed a fluorescent sensor based on polyethylene glycol (4 0 0) (PEG-400)-modified and H 2 O 2 -assisted etched sulfur quantum dots (SQDs). According to the fluorescence inner filter effect (IFE), the fluorescence of SQDs can be quenched by the p-nitrophenol (PNP) generated by NAG-catalyzed hydrolysis of p-Nitrophenyl-N-acetyl-β-D-glucosaminide (PNP-NAG). We successfully used the SQDs as a nano-fluorescent probe to detect the NAG activity from 0.4 to 7.5 U·L−1, with a detection limit of 0.1 U·L−1. Furthermore, the method is highly selective and was successfully used in the detection of NAG activity in bovine serum samples, suggesting its great application prospect in clinical detection. [ABSTRACT FROM AUTHOR]

AIMS Polymyxin E was used for treating gram-negative bacterial infections but not recently for fear of its nephrotoxicity. Silybin has potential to counteract nephrotoxicity; however, few studies have investigated its protective effect on the kidney in an animal model. The purpose of the present study was to assess whether silybin could decrease elevated urine and serum renal biochemical markers induced by polymyxin E in rat kidney. METHODS Forty rats were divided randomly into four groups of 10 rats: control (I), vehicle (II), treatment (III, using polymyxin E), and protection (IV, using silybin and polymyxin E). Urine was collected daily for 7 days to test for N-acetyl-beta-D-glucosaminidase (NAG). Serum was collected after euthanizing the rats on day 7 to test kidney functions. RESULTS Group III had significant increases in NAG (all P < 0.001) compared with the other groups, but no differences were found between the other groups. Significant differences in kidney functions were found between Group III and Groups I and II, and between Group IV and Groups I and II (all P < 0.001). No differences were found between Groups III and IV. CONCLUSIONS Group III results suggested an affection of the renal glomeruli and tubules, and Group IV results suggested a possible protective effect of silybin against polymyxin E-induced nephrotoxicity. Additional studies are recommended that use different doses of silybin for Groups III and IV to test for statistical differences for kidney functions and that test the protective effect of silybin against nephrotoxicity induced by polymyxin E in humans. [ABSTRACT FROM AUTHOR]

N-acetyl-beta-D-glucosaminidase (NAG) is a lysosomal enzyme present in the proximal convoluted tubules of the kidneys that may be used as a marker of proximal tubular damage and nephrotoxicity. An abnormal urinary NAG excretion has been reported in different kinds of renal disorders such as acute kidney injury, urinary tract infection, vesicoureteral reflux; diabetes mellitus; nephrotic syndrome; glomerulonephritis; hypertension; perinatal asphyxia; heavy metals poisoning; drug nephrotoxicity, renal allograft rejection; and heart failure. This paper provides an overview of the diagnostic value of urinary NAG in the nephrourology field. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Clinical studies have demonstrated that tubulointerstitial rather than glomerular pathology correlates with the degree and progression of renal impairment. Urinary n-acetyl-beta- D-glucosaminidase (NAG) is a biomarker of tubular damage, shown to be elevated in patients with glomerulonephritis and acute kidney injury. However, it has not been assessed longitudinally in chronic kidney disease (CKD). The aim of the present study was to determine urinary NAG activity and its possible associations with metabolic and inflammatory parameters in CKD. MATERIAL and METHODS: A total of 72 patients (mean age: 64.5±15.7) with stage 1-5 CKD were included. Of the 72 patients 23 (32%) had diabetic nephropathy and 49 (68%) had different types of primary glomerular diseases. Fasting blood samples were collected to analyse complete blood count, urea, creatinine, albumin, lipid parameters, C-reactive protein, uric acid and parathyroid hormone. 24-hour urine was collected to determine protein excretion. Urinary NAG and creatinine levels were analysed from the first morning urine samples. The NAG index (urinary NAG/ creatinine) was used to exclude dilutional errors. RESULTS: Mean eGFR was 38.3±21.7 ml/min. The urinary NAG index was significantly higher in stage 3 compared to stage 2 (32.1±23.5 vs. 7.5±3.3 U/gr-creatinine; p=0.002) and lower in stage 5 compared to stage 3 CKD (8.2±7.6 vs. 32.1±23.5; p=0.017). The urinary NAG index was positively correlated with 24-hour urine protein excretion (r=0.43; p=0.0001) and serum CRP (r=0.549; p=0.04) and negatively correlated with hemoglobin levels (r-0.394; p=0.004). CONCLUSION: The present study demonstrated that urinary NAG correlates with systemic inflammation and proteinuria and may be associated with progression of CKD. [ABSTRACT FROM AUTHOR]

Objectives: Renal involvement is common in sickle cell disease (SCD). Early demonstration of renal injury and commencement of appropriate treatment will increase survival and quality of life in these patients. We investigated renal manifestations in our pediatric and adult SCD patients and evaluated the role of cystatin C, Beta2 microglobulin (B2M), retinol-binding protein (RBP), N-acetyl-beta-D-glucosaminidase (NAG), and endothelin-1 (ET-1) to indicate renal damage. Methods: The study involved 45 pediatric and 10 adult patients with SCD and 20 healthy children and 10 healthy adults as a control. All the patients were questioned for possible renal manifestations. 24-hour urine samples were collected and glomerular filtration rates (GFRs) were calculated by using creatinine (GFRcreatinine), Schwartz formula (GFRSchwartz), and cystatin C (GFRcystatin C). Blood and urine samples were collected and serum cystatin C, urine B2M, RBP, NAG, and ET-1 levels were measured. Results: Nocturnal enuresis and proteinuria were the most common renal manifestations in SCD patients. When the groups were compared in terms of GFR, GFRcreatinine and GFRSchwartz levels were higher in group 1 and 2 patients than in control 1 and 2 patients ( P < .05). Cystatin C, B2M, RBP, NAG, and ET-1 values were normal in both the patient and the control groups. However, B2M/creatinine levels were higher than 160 μg/mg creatinine levels in 10 patients. Conclusions: Serum cystatin C, urine NAG, RBP, and ET-1 levels were found to be insufficient for the evaluation of SCD nephropathy. Increased B2M/creatinie levels can be valuable in estimating possible glomerular and tubular damage in SCD. [ABSTRACT FROM AUTHOR]

Abstract: Background: We investigated whether melamine concentrations in 1-spot overnight urine sample can represent the previous 8- and 24-h total urinary melamine excretions in school children. The relationship between urinary melamine levels and several clinical biomarkers of early renal injury such as microalbumin and N-acetyl-beta-d-glucosaminidase (NAG) in urine was also examined. Methods: School children, aged 6–10y, and their parents who were healthy and lived closely to Kaohsiung Medical University-affiliated hospitals were recruited. All study children had the first 1-spot overnight urine sample collected on the Sunday morning (the first day) immediately when they woke up, and then all the subsequent urine samples continued to be collected until the first 1-spot overnight urine sample on the morning of the next day (Monday, the second day). Two first 1-spot overnight urine samples from their parents on the same Sunday and Monday mornings were also collected. This protocol was completed in the July and August of 2011. All urine samples were measured for melamine, biomarkers of early renal injury, and creatinine. Results: There were 7 girls and 16 boys in this study. Except for one missing urine sample from 1-spot overnight urine sample on the morning of the second day, melamine levels in the rest of urine samples among the study children were all detectable. The median melamine levels of 1-spot overnight urine samples on the first and second day mornings were 0.93 and 1.73μg/mmol of creatinine respectively. We found that melamine concentrations of 1-spot overnight urine samples on the second day morning were highly correlated with the previous 8- and 24-h total melamine excretions in urine (r=0.936, p<0.001, n=21 and r=0.616, p<0.001, n=21 respectively). Good correlation of 1-spot overnight urine sample on the first and second day mornings was also found (r=0.619, p=0.003, n=21). In contrast, there were no significant correlations of 24-h total urinary melamine and 24-h total urinary microalbumin and NAG excretions (r=−0.221, p=0.319, n=22 and r=0.084, p=0.710, n=22). Conclusion: Melamine levels in 1-spot overnight urine sample can predict the previous 8- and 24-h total melamine excretions in urine. Since melamine exposure levels in these school children were relatively low, its association with clinical biomarkers of early renal injury was not found. A future study is necessary to increase the sample size and to find the more sensitive preclinical biomarkers of renal injury to link with low melamine exposure in children in the community. [Copyright &y& Elsevier]

Renal tubulointerstitium plays an important role in the development and progression of diabetic nephropathy. The aim of this study was to assess serum cystatin C and 2 renal tubular enzymes, neutrophil gelatinase associated lipocalin (NGAL) and N-acetyl-beta-D-glucosaminidase (NAG), as screening markers for early renal dysfunction in patients with type 2 diabetes mellitus (T2DM). ROC curve analysis showed that urinary NAG is the most sensitive marker of microalbuminuria and early renal damage with sensitivity of 83.3%, while serum cystatin C was the most sensitive and specific marker of macroalbuminuria and damage progress with sensitivity of 70.8% and specificity of 83.3% versus 70.6% and 83.3% for uNGAL; and 64.7% and 66.7% for NAG, respectively. Our data indi­cate that urinary NAG is the most sensitive marker for early renal damage in diabetic patients. However, for damage progress, serum cystatin C is the most sensitive and specific marker for follow-up and monitoring renal dysfunction. [ABSTRACT FROM AUTHOR]

Abstract: The introduction of prenatal ultrasonography as a screening method entails an increasing number of infants diagnosed with prenatal hydronephrosis. Ureteropelvic junction obstruction accounts for 35% of prenatal hydronephrotic cases. Urinary tract obstruction that occurs during early kidney development affects renal morphogenesis, maturation and growth, and in the most severe cases this will ultimately cause renal insufficiency. A major challenge in the clinical management of these patients is to preserve renal function by selection of the 15%–20% who require early surgical intervention, leaving those for whom watchful waiting may be appropriate because of spontaneous resolution/stabilization without significant loss of renal function. Today, this requires medical surveillance, including repetitive invasive diuretic renograms relying on arbitrary threshold values, and therefore there is a need for non-arbitrary, non-invasive urinary biomarkers that may be used as predictors for renal structural changes and/or decreasing renal function, and thereby provide the surgeon with more clear indications for surgical intervention. In this review, we summarize the currently well-known facts about urinary biomarkers in ureteropelvic junction obstruction concerning renal function, and we also suggest potential novel urinary biomarkers. [Copyright &y& Elsevier]

An increased level of serum N-acetyl-ß-D-glucosaminidase can often be found in alcohol addicts. A statistically significant increase in the catalytic concentrations of NAGA and its isozymes was determined in a group of subjects with the diagnosis of liver cirrhosis and in an alcohol addicts' group in comparison to the control group. There was no statistically significant difference in the catalytic concentrations of NAGA and its isoenzymes between the subjects' group with liver cirrhosis without an alcohol genesis and the alcohol addicts' group. Furthermore, a statistically significant difference was found between the control group and the alcohol addicts' group. This is why it is important to determine the total level of catalytic NAGA concentrations as well as the catalytic concentrations of its isozymes when diagnosing alcohol dependence. The obtained results indicate that the determination of the catalytic NAGA concentrations is not a highly specific marker for alcoholism. The aim of the present paper was to examine the NAGA concentration in alcohol addicts treated at the Department of Psychiatry, and to question its value as a marker for alcohol dependence. Subjects treated from alcohol addiction as inpatients and patients with liver cirrhosis not caused by the alcohol's toxic activity took part in the study. The control group consisted of healthy volunteers. When compared to the healthy volunteers, alcohol addicts showed a statistically higher NAGA concentration in serum. [ABSTRACT FROM AUTHOR]

[Display omitted] • A major public health issue in Taiwan in 2011 involved phthalate-tainted foods. • This cohort study followed three waves in affected children over five years. • Past daily DEHP intake from DEHP-tainted foods and time had significant effects on urinary ACR, with negative interactions. • Urinary melamine levels increased urinary ACR and oxidative stress over time. • Impact of DEHP-tainted foods on urinary ACR was highest in the first wave and diminished gradually. In 2011, phthalates, mainly di-(2-ethylhexyl) phthalate (DEHP), were found to have been added to a variety of foods in Taiwan, increasing the risk of microalbuminuria in children. Exposure to melamine perhaps modifies that risk. This prospective cohort study investigates whether renal injury resulting from exposure to DEHP-tainted foods from the 2011 Taiwan Food Scandal is reversed over time. The temporal and interactive effects of past daily DEHP intake, current daily DEHP intake, and urinary melamine levels on oxidative stress and renal injury were also examined. Two hundred possibly DEHP-affected children (aged < 18 years) were enrolled in the first survey wave (August 2012–January 2013), with 170 and 159 children in the second (July 2014–February 2015) and third waves (May 2016–October 2016), respectively. The first wave comprised questionnaires that were used to collect information about possible past daily DEHP intake from DEHP-tainted foods. One-spot first morning urine samples were collected to measure melamine levels, phthalate metabolites, and markers indicating oxidative stress (malondialdehyde and 8-oxo-2′-deoxyguanosine), and renal injury (albumin/creatinine ratio (ACR) and N-acetyl-beta-D-glucosaminidase) in all three waves. Generalized estimating equation (GEE) modeling revealed that both past daily DEHP intake and time might affect urinary ACR. However, most interactions were negative and significant correlation was observed only during the second wave (P for interaction = 0.014) in the group with the highest past daily DEHP intake (>50 μg/kg/day). Urinary melamine levels were found to correlate significantly with both urinary ACR and oxidative stress markers. The highest impact associated with exposure to DEHP-tainted foods in increasing urinary ACR of children was observed during the first wave, and the effect may partially diminish over time. These results suggest that continuous monitoring of renal health and other long-term health consequences is required in individuals who were affected by the scandal in 2011. [ABSTRACT FROM AUTHOR]

Background: Nephropathy is a well-known complication of congenital heart disease (CHD), and the risk of developing renal impairment is particularly high in patients with cyanotic CHD. Most investigations of renal impairment in CHD have involved patients 20 years and older. This study investigated renal tubule function in pediatric patients with CHD, and compared findings in cyanotic and acyanotic groups. Methods: Twenty children with acyanotic CHD, 23 children with cyanotic CHD, and 13 healthy children were enrolled. Blood and early morning urine samples were collected from each subject to measure urinary concentrations of sodium, microalbumin, creatinine, β2-microglobulin, and N-acetyl-β-D-glucosaminidase (NAG). Results: The age and sex distributions in the three groups were similar. Median fractional excretion of sodium (FeNa) and urinary NAG/creatinine were significantly higher in the cyanotic group than in the control group (p = 0.022 and p = 0.002, respectively). There were no statistically significant differences among the groups with respect to urinary β2-microglobulin/creatinine, urinary microalbumin/creatinine or glomerular filtration rate. Conclusion: Tubular injury can be detected before glomerular injury occurs even within the first decade of life in patients with cyanotic CHD. Copyright © 2005 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]

The iso-enzyme profiles of urinary N-acetyl-β-D-glucosoaminidase (NAG) were studied in the workers from a chloro-alkaline electrolysis plant that had been continuously exposed to elemental mercury. The same workers then had a work break of four months and were later re-exposed to mercury for another five months. The activities of urinary NAG in workers exposed to mercury before and after the work break and in the control group were 2.09±1.03 IU/L; 0.90±0.52 IU/L and 1.13±0.35 IU/L, respectively. The fraction of the dominant A form activity in the total activity, in the workers exposed to mercury after a work break (85.31±5.32%), was almost equal to the fraction of A in the control group (84.64±2.75%). The percent fraction of A forms (A and A[sub 2]) during continuous exposure was almost equal to the sum of the fractions A and A[sub 2] in the control group and for exposure after the work break. The fraction of the B form activity in the total activity during exposure to elemental mercury for five months after the work break (7.41±3.45%) was lower (P < 0.1) than the fraction of the B form in the control group (8.62±2.19%). The decrease in the fraction of the B form compared with the control group was more significant (P <0.001) in the case of continuously exposed workers (5.25±2.55%). Beside the major A and B iso-enzymes of NAG, the A[sub 2] form was also isolated, and its fraction in the control group (6.73±2.15%) was not negligible. For workers exposed to mercury for five months, it was 7.28±3.52%. It is concluded that mercury affected the increased exocytosis of iso-enzyme A and the inhibition of B iso-enzyme of NAG. The increase in activity of urinary NAG in subjects exposed to mercury was a consequence of the increased excretion of A form. It was established also that the four months work break was sufficient for the repair of renal damages that occurred during continuous exposure, and which were monitored by the activity of NAG. Thus, the effects of mercury seem to have been reversible. [ABSTRACT FROM AUTHOR]

A single oral dose of sodium fluoride (NaF) in aqueous solution was given to male Wistar rats. Twenty-four-hour urine samples were collected and examined to evaluate fluoride-induced acute renal damage. The following parameters were measured in 24-h urine: urine volume and urinary excretion of fluoride, N-acetyl-β- d-glucosaminidase (NAG), α-glutathione-S-transferase (α-GST), and creatinine (CR). Fluoride exposure produced specific, dose-dependent changes of these parameters. Significant increases of fluoride and fluoride-induced polyuria were observed. NAG as specific marker of proximal convoluted tubule (PCT) function showed a significant increase when the lowest dose of fluoride was administered. At this minimal dose, α-GST, a specific marker for the S3 segment, did not show a significant increase but presented the strongest relationship ( r = 0.83) to fluoride dose. No significant changes were measured for CR excretion, which showed a low correlation coefficient ( r = 0.36) to administered fluoride. The specific differences in the increase pattern of these parameters show that the PCT is more susceptible to damage by low-dose fluoride than the S3 segment or the glomerulus. We concluded that both NAG and α-GST are useful for the diagnosis of fluoride-induced acute nephrotoxicity. Proper evaluation of these urinary indices may be of help to establish the site and extent of kidney injury in acute fluoride toxicity. [ABSTRACT FROM AUTHOR]