N-acetyl-β-D-glucosaminidase Activity Research Articles

Responses of N-Cycling Enzyme Activities and Functional Diversity of Soil Microorganisms to Soil Depth, Pedogenic Processes and Cultivated Plants

The rates of N cycling and soil enzyme activities involved in the transformation of soil N-related nutrients are rarely measured in soils below a 30 cm depth, even though substantial amounts of nitrogen are also stored in deep soils. The aim of this study was to determine how soil microbial and enzymatic properties changed as a function of depth across soil profiles that were developed on the same parent material but differed in terms of soil-forming processes. Two soil profiles were excavated in fields with lucerne and two under winter wheat. We assessed the N-cycling enzymes, the microbial utilization of the N-substrates, the microbial biomass carbon and nitrogen (MBC, MBN) content, and the related physicochemical properties. The most beneficial enzymatic (on a soil mass) and microbial properties, as well as nitrogen substrate utilization, were found in the Ap horizons and decreased with depth to varying degrees. The specific enzymatic activity (per unit of soil TOC and MBC), was more variable in response to the depth of the profile, but did not exhibit clear trends. The potential enzyme activities in the subsurface layers were also affected by factors that are associated with the pedogenic processes (e.g., the lessivage process, clay content). Only nitrate reductase activity was significantly higher in the horizons with potential reducing conditions compared to oxidative horizons, while the opposite trend was found for N-acetyl-β-D-glucosaminidase (NAG) activity. The cultivated plants had a significant impact on the degree of enzymatic activity and N-substrate utilization. The lessivage process significantly reduced microbial biomass and enzymatic activity (except for NAG activity). In general, nitrogen substrate utilization decreased with increasing soil depth and was greater in lucerne than the winter wheat profiles. Mollic Stagnic Gleysols (MSG) and Cambic Stagnic Phaeozems (CSP) horizons also have higher nitrogen substrate utilization than Luvisol profiles.

N-acetyl-β-d-glucosaminidase activity assay for monitoring insulin-dependent diabetes using Ag-porous Si SERS platform

Determination of urinary or serum N-acetyl-β-d-glucosaminidase (NAG) activity as a tissue damage indicator is widely used in diagnosis of various pathologies, including diabetic nephropathy. Early and rapid biomarker detection is an important element of medical diagnosis, facilitating prompt therapeutic decisions and prognosis evaluation. Herein, we present a modified sensing approach for a rapid and reliable NAG activity determination in complex media using surface-enhanced Raman spectroscopy (SERS). Porous silicon (PSi) Fabry-Pérot interferometers were redesigned as sensitive SERS platforms utilizing the vast inherent surface area for silver (Ag) nanoparticles embedment. Interaction of the porous nanostructures with specific NAG-enzymatic products produces an indicative spectral fingerprint proportional in magnitude to its concentration. The sensitivity of Ag–PSi SERS substrates was evaluated in complex matrices presenting sufficient limits of detection compared with other advanced assays and techniques (0.07, 0.47 and 0.50 mU mL−1 for urine, milk and plasma, respectively). The augmented optical performance revealed recovery values of 96–109%, indicating successful and selective NAG recognition in biological fluids. Finally, the potential applicability of the suggested prototype for real-life scenarios was evaluated in vivo, in a model of insulin-dependent diabetes induced in sheep. Overall, the robust data confirm the application of SERS analysis for early diagnosis of pathology and for evaluation of clinical responses to pharmacological treatments.

DNA aptamer raised against receptor for advanced glycation end products suppresses renal tubular damage and improves insulin resistance in diabetic mice.

Objective:Interaction of advanced glycation end products (AGEs) with the receptor RAGE plays a role in diabetic nephropathy. However, effects of RAGE-aptamer on tubular damage remain unknown. We examined whether RAGE-aptamer inhibited tubular damage in KKAy/Ta mice, obese type 2 diabetic mice with insulin resistance.Materials and Methods:Male 8-week-old KKAy/Ta mice received continuous intraperitoneal infusion of either control-aptamer or RAGE-aptamer for 8 weeks. Blood biochemistry and blood pressure, and urinary N-acetyl-β-D-glucosaminidase (NAG) activity and albumin excretion levels were monitored. Kidney and adipose tissue samples were obtained for immunohistochemical analyses.Results:Although RAGE-aptamer did not affect blood glucose, blood pressure, body weight, or serum creatinine values, it significantly inhibited the increase in urinary NAG activity and HOMA-IR in diabetic mice at 12 and 16 and at 16 weeks old, respectively. Furthermore, compared with control-aptamer-treated mice, renal carboxymethyllysine, RAGE, and NADPH oxidase-driven superoxide generation were significantly decreased in RAGE-aptamer-treated mice at 12 weeks old with subsequent amelioration of histological alterations in glomerular and interstitial area, while adipose tissue adiponectin expression was increased.Conclusion:Our present results suggest that RAGE-aptamer could inhibit tubular injury in obese type 2 diabetic mice partly by suppressing the AGE-RAGE-oxidative stress axis and improving insulin resistance.

Dynamics of Restoration of Functional State of the Kidney Parenchyma and Normalization of Main Risk Factors of Calcium-oxalate Nephrolithiasis in Urine on the Background of Using Complex Metaphylaxis

The objective: to investigate the dynamics of restoration of the functional state of the renal parenchyma by levels of N-acetyl-β-D-glucosaminidase (NAG) activity in urine and normalization of the main risk factors of calcium-oxalate nephrolithiasis (Ca-Ox NL) – by concentrations of calcium, oxalic and uric acids in urine on the background of application of complex metaphylaxis within a year after stone removal.Materials and methods. 45 patients with Ca-Ox NL before and after the removal of concrements in 1, 3, 6 and 12 months on the background of the use of complex metaphylaxis were examined. The activity of the conditionally renospecific enzyme NAG and concentration of calcium, oxalic and uric acids were analyzed. The personification of metaphylactic measures was performed depending on the characteristics of the risk factors for the development of Ca-Ox NL: the combination of hyperoxaluria with hyperuricemia and hyperuricuria, the combination of hyperoxaluria with hyperuricemia, the presence of significant hyperoxaluria on the background of normouricemia and normouricuria and also depending on hypercalciuria. The control group consisted of 28 practically healthy persons with normal analysis of urine and free of renal diseases.Results. In patients with NL before the removal of the stone, the activity of NAG, calcium, oxalic and uric acid concentrations probably exceeded the control data. In the dynamics of observation there is a gradual decrease in urinary NAG activity, calcium, oxalic and uric acid concentrations. NAG activity and uric acid concentration did not differ from the data in the control group after 12 months, calcium – after 3 months, oxalic acid concentration after 6 months.Conclusion. Restoration of the functional state of tubular nephrotheoia and normalization of concentrations of the main risk factors for the development of Ca-Ox NL on the background of complex metaphylaxis was achieved in almost 95 % of cases. The obtained results can be used to correct and optimize the treatment tactics of patients with Ca-Ox NL after removal of the calculus during the year.

Effect of non-steroidal anti-inflammatory drugs on glomerular filtration rate and urinary N-acetyl-β-D-glucosaminidase activity in cats after dental surgery

ObjectiveTo compare the effects of meloxicam or carprofen on glomerular filtration rate (GFR), and to evaluate the effect of meloxicam on urinary N-acetyl-β-D-glucosaminidase (NAG) activity, of cats after dental surgery. Study designRandomized, blinded, controlled trial. AnimalsA total of 24 mixed breed cats. MethodsCats were randomly assigned to one of three groups (n = 8 per group): meloxicam (0.2 mg kg–1); carprofen (4 mg kg–1); or saline (2 mL). Acepromazine (0.04 mg kg–1) and buprenorphine (0.02 mg kg–1) were administered intramuscularly as preanaesthetic medication. Test drugs were injected subcutaneously at the time of preanaesthetic medication. Anaesthesia was induced with intravenous propofol and maintained with isoflurane in oxygen. Mean arterial blood pressure (MAP), respiratory rate (fR), heart rate (HR) and haemoglobin oxygen saturation values (SpO2) were recorded. All cats underwent ultrasonic dental scaling with polishing. Teeth extraction involved mucosal flap creation, removal of alveolar bone and flap closure. Plasma iohexol clearance (ICL), a measure of GFR, was estimated before and 24 hours after anaesthesia induction in all cats. Urinary NAG index was estimated in saline and meloxicam groups at the same time points as GFR. Between-group and -time point differences in GFR and NAG index were compared using mixed model analyses. Data are presented as mean ± standard deviation (p < 0.05). ResultsThere was no significant difference in plasma ICL rate (range: from 1.22 ± 0.05 to 1.27 ± 0.04 mL kg minute–1) between groups or between time points. Urinary NAG index (range: from 1.0 ± 0.19 to 1.36 ± 0.29 Units gram–1) was not significantly different between meloxicam and saline groups. MAP, HR, fR and SpO2 did not differ significantly between groups. Conclusions and clinical relevanceMeloxicam and carprofen appeared to produce nonsignificant effects on GFR, and meloxicam did not affect the urinary NAG activity, of cats after dental surgery.

Carbon dots as fluorescent nanoprobe for the determination of N-acetyl-β-d-glucosaminidase activity

Carbon dots (CDs) were synthesized from p-aminophenol and ethylenediamine via one-step under mild condition and used as a sensitive fluorescent nanoprobe for the activity determination of N-acetyl-β-d-glucosaminidase (NAG). In this assay, p-nitrophenol was in situ produced from p-nitrophenyl-β-D-N-acetyl-glucosaminide, which was exclusively hydrolyzed by NAG. The UV absorption peak of p-nitrophenol (maximum at 400 nm) overlapped the excitation peak of CDs with maximum wavelength at 415 nm, which caused the fluorescence decline of CDs based on inner filter effect. The activity of NAG was determined by the fluorescence changes. The assay is highly sensitive to NAG with a low detection limit of 0.75 U L−1 (K = 3) and showed a good linear relationship in the range from 1 to 45 U L−1. This CDs nanoprobe was successfully applied for the determination of NAG activity in human serum and urine samples.

Effect of infliximab, a tumor necrosis factor-alpha inhibitor, on doxorubicin-induced nephrotoxicity in rats.

Treatment with the chemotherapeutic agent, doxorubicin (DOX), is limited by nephrotoxicity. We investigated the possible protective effect of infliximab, a tumor necrosis factor alpha (TNF-α) inhibitor on DOX-induced nephrotoxicity. Rats were treated with a single intraperitoneal (ip) injection of DOX (17.5mg/kg) in the absence or presence of infliximab (5mg/kg, i.p.). Plasma and urinary markers of kidney function, oxidative stress, and inflammation were measured. Kidney and heart tissue was evaluated histopathologically. DOX-induced nephrotoxicity was confirmed by increased plasma urea, creatinine, cystatin C, neutrophil gelatinase-associated lipocalin (NGAL), and clusterin concentrations. In addition, DOX increased urinary albumin/creatinine ratio, N-acetyl-β-D-glucosaminidase (NAG) activity, kidney injury molecule (KIM-1) concentrations, and reduced creatinine clearance. DOX significantly reduced renal antioxidants and increased plasma inflammatory markers and adiponectin concentrations. Concomitant treatment with infliximab did not significantly affect DOX-induced changes in plasma creatinine, cystatin C, or creatinine clearance. However, infliximab significantly reduced DOX-induced action on plasma urea, NGAL, clusterin, and adiponectin. Infliximab also significantly reduced urinary albumin/creatinine ratio, NAG activity, and KIM-1 concentrations, as well as the occurrence of fibrotic lesions in kidney tissue. Fibrosis detected in the heart was unchanged. In addition, infliximab reduced DOX-induced effects on plasma inflammatory markers, renal superoxide dismutase (SOD) and total antioxidant capacity. Our results show that infliximab is partially effective in mitigating DOX-induced nephrotoxicity in rats.

Determination of the reference interval for the activity of N-Acetyl-β-D-Glucosaminidase (NAG) in urine of healthy dogs

ABSTRACT: The diagnosis of acute kidney injury by evaluating the activity of urinary enzymes is an important tool especially for its precocity in relation to methods of assessment of renal function considered late as the installation of injury precedes the function change. This study was performed to determine the reference interval for urinary NAG activity (N-Acetyl-β-D-glucosaminidase) in urine of healthy dogs of different breeds, ages and sexes. It was utilized an automated method for the determination of NAG activity standardized for dog urine samples. Through statistical analysis it was observed that NAG is positively correlated with the age of the animal and urine specific gravity but is not interfered by sex or weight. Based on the determination of urinary activity and after correcting the values for a 1,025 urine specific gravity was obtained an reference interval of X ‘= 3.62U/L±0.66U/L.

Low molecular weight proteins and enzymes in the urine of patients with bladder cancer - a pilot study.

IntroductionA steady increase in cases of bladder cancer (BC) has been observed. Detection of unfavorable changes, especially in the early stages of disease, is crucial to medical procedure. There is still a need to search for new, non-invasive biomarkers of BC. The aim of this study was to estimate the levels of selected low molecular weight proteins (LMWP) and enzymes in the urine of patients at different BC stages and grades.Material and methodsUrine samples from 46 patients with BC and 16 healthy controls were examined. We measured levels of LMWP such as: retinol-binding protein (RBP), β2 -microglobulin (β2M), enzymes: N-acetyl-β-D-glucosaminidase (NAG), isoform (NAG-B) and also neutrophil gelatinase-associated lipocalin (NGAL).ResultsThe levels of all examined parameters differed between patients and healthy subjects. Levels of NAG (p = 0.031), NAG-B (p = 0.023) and NGAL (p = 0.008), and total protein (p = 0.007) concentrations, were significantly higher in the BC patients than in the control group. Among the examined parameters, positive significant correlations were observed only between urinary NGAL concentration and tumor stages and grades. The highest percentages of changes in NGAL concentration were observed in tumor in situ (TIS) and G3grade patients.ConclusionsOur study showed that urinary NGAL concentrations, as well as NAG and NAG-B activity, could be helpful noninvasive parameters for the diagnosis of BC. The most promising seems to be NGAL determination, but further study is needed on a larger group of participants in order to confirm this observation.

Low-Level Environmental Cadmium Exposure Induces Kidney Tubule Damage in the General Population of Korean Adults.

Cadmium (Cd) is the most potent nephrotoxic heavy metal and may affect bone; it also has a long biological half-life in the human body. This study was designed to assess the effect of environmental low-level Cd exposure on kidney function and bone in the general population. The subjects of this cross-sectional study were 1907 healthy Korean adults who had not been exposed to Cd occupationally. We analyzed the concentrations of Cd in the urine, markers of renal tubule damage, such as β2-microglobulin (β2-MG) and N-acetyl-β-D-glucosaminidase (NAG) activity in the urine, calculated the estimated glomerular filtration rate (eGFR) using serum creatinine, and measured bone mineral density (BMD). Also, we analyzed malondialdehyde (MDA) levels in the urine. The geometric mean concentration of Cd in urine was higher in women (1.36μg/g creatinine) than in men (0.82μg/g creatinine). Urinary Cd was significantly positively correlated with urinary β2-MG and NAG activity, whereas it was negatively correlated with eGFR and BMD. The risk of renal tubule damage was significantly associated with urine Cd level, and the association remained significant after controlling for various confounding variables. However, no association was observed between urinary Cd level and glomerular dysfunction or bone damage. The concentration of MDA was increased with urinary Cd level in a dose-dependent manner. These findings suggest that low-level environmental Cd exposure may cause microscopic damage to renal tubules through oxidative stress but might not impair kidney glomeruli or bones.

Effects of elevated nitrogen and precipitation on soil organic nitrogen fractions and nitrogen-mineralizing enzymes in semi-arid steppe and abandoned cropland

Soil organic nitrogen (N) turnover is significantly influenced by elevated N deposition, precipitation and human-caused disturbances, but the underlying mechanism remains unclear. Identifying the relationships among the soil organic N fractions and N-mineralizing enzymes activities may advance our knowledge of the dynamics of soil organic N. A field experiment was conducted in a semi-arid steppe and an abandoned cropland in northern China to investigate the effects of elevated N deposition and precipitation on soil organic N fractions and their relationships with N-mineralizing enzymes, i.e., protease, amidase, urease and N-acetyl-β-D-glucosaminidase (NAG) activities. The concentrations of N in various fractions were consistently lower in the abandoned cropland compared with the steppe. Nitrogen addition consistently decreased amino acid N content and activities of urease, protease and amidase in both sites but increased amino sugar N content and NAG activity in the steppe. Water addition decreased hydrolysable ammonium N content but increased amino sugar N content and activities of protease and NAG in both sites. Furthermore, urease and NAG activities were significantly positively correlated with the proportions of amino acid N and amino sugar N and, explained significant proportions of the variations in soil organic N fractions in the steppe. However, soil organic carbon (C), rather than N-mineralizing enzymes, explained greatest proportion of the variations in soil organic N fractions in the abandoned cropland. The concurrent increase of N deposition and precipitation could promote the recovery of soil N (and C) losses in the abandoned cropland resulting from previous agriculture. Furthermore, in the steppe where NH4 + was available at relative high concentrations, enzymatic mineralization was the dominant route involved in potential soil organic N turnover. However, the direct route may be favored over the enzymatic mineralization route with decreasing availability of C relative to N in the abandoned cropland, which is driven by the need for C. These findings confirmed that the forms of N available, and the relative availability of C and N determine N uptake pathways both through enzymatic mineralization route and direct uptake route in the semi-arid grasslands.

Nanoparticle formulation increases Syzygium cumini antioxidant activity in Candida albicans-infected diabetic rats

Context: Syzygium cumini (L.) Skeels (Myrtaceae) is a medicinal plant widely used in folk medicine for the treatment of diabetes mellitus (DM). However, studies on the use of this plant and of nanoparticle formulations against DM-related fungal infections are scarce.Objective: To evaluate the effect of the treatments with aqueous seed extract of S. cumini (ASc) and ASc-loaded polymeric nanoparticles (NPASc) on biochemical parameters in Candida albicans-infected diabetic rats.Materials and methods: Male Wistar rats were divided into eight groups: Control, DM, C. albicans, C. albicans + ASc, C. albicans + NPASc, DM + C. albicans, DM + C. albicans + ASc and DM + C. albicans + NPASc. Rats were daily treated with ASc or NPASc (100 mg/kg) for 21 days. Biochemical parameters in serum and urine, advanced oxidation protein product (AOPP) and TBARS levels in the serum, kidney, liver and pancreas and N-acetyl-β-d-glucosaminidase (NAG) activities in kidney and urine were evaluated.Results: Biochemical and oxidative stress parameters increased in rats with DM and/or candidiasis. NPASc was more effective than ASc in decreasing glucose (56%), cholesterol (33%) and creatinine (51%) levels; serum (16%) and pancreatic (46%) AOPP and renal (48%) TBARS levels when compared with DM + C. albicans group. In C. albicans group, both treatments decreased NAG activity but did not decrease creatinine levels.Conclusions: These data suggest that the use of nanotechnology is able to improve plant extract properties such as antioxidant activity that may be useful in diabetes-related complications.

Renal tissue pro-inflammatory gene expression is reduced by erythropoietin in rats subjected to hemorrhagic shock.

BackgroundHemorrhagic shock (HS) is a condition produced by considerable loss of intravascular volume, which may eventually lead to organ damage and death.ObjectivesIn the present study, the potential implication of the kidney tissue tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), and interleukin-10 (IL-10) were evaluated in the protective effects of erythropoietin (EPO) during HS.Materials and MethodsMale Wistar rats were randomized into three experimental groups; Sham, HS (hemorrhagic shock and resuscitation), and EPO (erythropoietin). HS was induced by 50% blood volume hemorrhage over 30 minutes. After 2 hours, resuscitation was performed within 30 minutes. In the EPO group, EPO (300 IU/kg, i.v.) was administered 10 minutes before HS induction. Urine was collected to determine urinary N-acetyl-β-D-glucosaminidase (NAG) activity level. The kidney cytokines (TNF-α, IL-6 and IL-10) mRNA expressions were measured by real-time polymerase chain reaction (PCR).ResultsHS rats showed significant increase in urinary NAG activity compared to the sham group. EPO significantly attenuated the rises in urinary NAG activity compared to the HS group. In the HS animals, renal TNF-α and IL-6 mRNA expressions increased whereas no difference was observed in IL-10 mRNA expression between the HS and sham groups. EPO was able to decrease renal TNF-α and IL-6 production and increase IL-10 mRNA expression.ConclusionsIn this study, we demonstrated that EPO attenuates kidney damage in rats subjected to HS. The beneficial effects of EPO may be at least partly mediated by modifications in the inflammatory cascade.

A metabolic profiling analysis of the nephrotoxicity of acyclovir in rats using ultra performance liquid chromatography/mass spectrometry.

Acyclovir (ACV) exposure is a common cause of acute kidney injury (AKI). The toxicity mechanism of ACV has always been a matter of debate. The present study investigated into the time-effect relationship and dose-effect relationship of ACV-induced nephrotoxicity in rats using metabonomics. Twenty-four rats were randomly divided into four groups: a 0.9% NaCl solution group, and 100, 300, and 600mg/kg ACV-treated groups; the ACV or vehicle solution was administered with a single intravenous injection. Urine was collected at different time periods (12h before administration, and 0-6h, 7-12h, and 13-24h after administration). Routine urinalysis was conducted by a urine automatic analyzer. Renal markers, including urine urea nitrogen, urine creatinine, and urinary N-acetyl-β-d-glucosaminidase (NAG) activity, were determined using established protocols. Urinary metabolites were evaluated using ultra performance liquid chromatography/mass spectrometry (UPLC/MS). In the ACV-treated rats, increased levels of protein (PRO), occult blood (BLD), white blood cell (WBC), and NAG activity in urine were observed, while the urine creatinine and urea nitrogen levels showed a decrease compared with the control. Moreover, urine metabolites significantly changed after the treatment with ACV, and all the effects induced by ACV were dose-time dependent. Finally, 4 metabolites (guanine, 4-guanidinobutyric acid, creatinine, and urea) were identified, which can be used for further research on the mechanism of ACV-induced nephrotoxicity.

The Toxicity of Aluminum Chloride on Kidney of Rats.

This study investigated the toxicity of aluminum chloride (AlCl3) exposure in the rat kidney. Forty male Wistar rats (5weeks old), weighing 110-120g, were randomly divided into four groups: control group (CG, 0g/L AlCl3), low dose group (LG, 0.4g/L AlCl3), mid dose group (MG, 0.8g/L AlCl3), and high dose group (HG, 1.6g/L AlCl3). Rats were administered AlCl3 in their drinking water for 120days. A variety of measurements were taken including superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) activities, malondialdehyde (MDA) concentration in the kidney and blood urea nitrogen (BUN), and cystatin C (Cys-C) concentrations in the serum. In addition, Al and β2-microglobulin (β2-MG) concentrations and the activity of N-acetyl-β-D-glucosaminidase (NAG) in the urine were determined. The results showed that in the AlCl3-treated groups SOD and GSH-PX activities were decreased, while NAG activity and Al, MDA, BUN, Cys-C, and β2-MG concentrations were increased, compared with the CG. This study indicates that AlCl3 exposure induces oxidative stress and suppresses kidney function.

Urinary Markers for Early Detection of Diabetic Nephropathy in Type 1 Diabetes Mellitus

Background: diabetic nephropathy (DN) is a serious complication of diabetic mellitus associated with increased risk of morbidity and mortality. Diagnostic markers to detect DN at early stage are important as early intervention can slow loss of kidney functions and improve patient outcomes. N-acetyl-β-d-glucosaminidase (NAG) is a lysosomal enzyme, present in high concentrations in renal proximal tubular cells, Gamma-glutamyltransferase (GGT) is an enzyme which located along the proximal tubular brush border, Malondialdehyde (MDA) is a highly toxic product, formed in part by lipid oxidation derived free radicals, Reactive carbonyl derivatives (RCDS) is an oxidative stress marker in urine, as a measure of the oxidative modification of proteins and bete-2-microglobulin is filtered by the glomerulus, absorbed and catabolized by the proximal tubules. The aim of this study is to investigate the urinary outcome of these markers as early detectors of diabetic nephropathy in type 1 diabetic children. Subjects and methods: This case-control study included 67 children with type 1 diabetes mellitus (33 male; 34 female), age (11.03±1.05 years) and thirty one age (10.58±1.11 years) and sex (13 male; 18 female) matched healthy children (13 male; 18 female). Type 1 diabetic children were further subdivided into microalbuminuric and normoalbuminuric subgroups according to microalbuminuria concentration (30 mg/ g creatinine). Age, sex, diabetic duration and the current daily insulin dose, and family history of diabetes, weight, height, body mass index, systolic and diastolic blood pressure were recorded. Fasting plasma glucose, glycated hemoglobin, blood urea nitrogen, plasma creatinine, urinary creatinine, micoalbumin, N-acetyl-B-D glucosaminidase (NAG), Gama glutamyl transferase (GGT), Beta-2-microglobulin, Malondialdehyde (MDA) and Reactive carbonyl groups (RCDSS) were measured in all subjects. Results: a significant increase in tubular injury markers of diabetes (NAG, GGT, beta-2-microglobulin) and oxidative stress parameters (MDA, RCDSS) as compared to control subjects was found. Microalbuminuric subjects showed a significant elevatation in the urinary markers including NAG, GGT, beta-2-microglobulin, MDA, RCDSS as compared to normoalbuminuric subjects. The studied urinary tubular enzymes (NAG, GGT), oxidative stress markers (MDA, RCDSS) and Beta-2- microglobulin showed positive correlations with one another. Conclusion: The results of this study introduced the possibility of depending on tubular enzymes (NAG, GGT), oxidative stress markers (MDA, RCDSS) and β2 microglobulin as early, reliable, and sensitive predictors for diabetic nephropathy. The NAG activity index proved to be the most sensitive biomarker, then beta-2- microglobulin for early discovering the tubule cells damage.

Efficacy of urinary N-acetyl-β-D-glucosaminidase to evaluate early renal tubular damage as a consequence of type 2 diabetes mellitus: a cross-sectional study

We assessed the prognostic accuracy of urinary N-acetyl-β-D-glucosaminidase (NAG), an early proximal tubular damage marker for the onset of diabetic nephropathy. The study included 491 eligible participants with 76 healthy controls, 194 type 2 diabetes mellitus (T2DM) patients with 0–5, 5–10, 10–15, and 15–20 years of T2DM duration, 71 microalbuminuric patients, 100 diabetic nephropathy patients, and 50 non-diabetic nephropathy patients. Fasting glucose, serum fructosamine, HbA1C, urinary microalbumin, serum creatinine, estimated glomerular filtration rate (eGFR), serum NAG, and urinary NAG were estimated. We compared urinary NAG activity with other well-established markers of diabetic nephropathy like microalbuminuria, eGFR, and serum creatinine. Urinary NAG excretion was increased by 8 and 12 folds in T2DM patients of 10–15 and 15–20 years of diabetes duration (p < 0.0001), respectively, without the appearance of microalbuminuria. The urinary NAG activity increased 16 and 18 fold in moderately increased albuminuria and diabetic nephropathy patients, respectively (p < 0.0001), without any change in non-diabetic nephropathy patients. A cutoff value of 3 U/L of urinary NAG has demonstrated a sensitivity of 96.1 % and a specificity of 100 % discriminating healthy controls from patients with T2DM duration of 10–15 years (AUC 1.000) and 15–20 years (AUC 0.999); microalbuminuria (AUC 0.999), and diabetic nephropathy (AUC 1.000). Urinary NAG excretion gradually increases with the increase in duration of diabetes and appeared much before the microalbuminuria, decreased eGFR, and increased serum creatinine. Thus, the urinary NAG may be considered as a potential site-specific early tubular damage marker leading to diabetic nephropathy.

Renal, gastrointestinal, and hemostatic effects of oral administration of meloxicam to Hispaniolan Amazon parrots (Amazona ventralis).

To investigate renal, gastrointestinal, and hemostatic effects associated with oral administration of multiple doses of meloxicam to healthy Hispaniolan Amazon parrots (Amazona ventralis). 12 Hispaniolan Amazon parrots. Birds were assigned to receive meloxicam oral suspension (1.6 mg/kg, PO, q 12 h) and 2.5 mL of tap water inserted into the crop by use of a gavage tube (n = 8) or the equivalent volume of tap water only (control group; 4) for 15 days. Urine and feces were collected 2 hours after treatment administration each day. Feces were evaluated for occult blood. Results of a CBC and serum biochemical analysis and measured N-acetyl-β-d-glucosaminidase (NAG) activity and whole blood clotting time were evaluated before, during, and after completion of treatments. Results of urinalysis and measured urine NAG activity were also evaluated. Birds treated with meloxicam had a significant increase in number of WBCs and decrease in PCV from before to after treatment. The PCV also decreased significantly, compared with results for the control group; however, WBC count and PCV for all birds remained within reference ranges throughout the study. One parrot treated with meloxicam had a single high value for urine NAG activity. Meloxicam administered orally at the dosage used in this study caused no apparent negative changes in several renal, gastrointestinal, or hemostatic variables in healthy Hispaniolan Amazon parrots. Additional studies to evaluate adverse effects of NSAIDs in birds will be needed.

Urinary N-acetyl-β-D-glucosaminidase (NAG) activity in the early detection of diabetic nephropathy

One of the serious outcomes of diabetes mellitus is nephropathy. Measurement of microalbuminuria is a routine clinical practice for screening the diabetic nephropathy, but the injury to the kidney may be happening even without microalbuminuria. The association between urinary enzyme activities of N-acetyl-β-D-glucosaminidase (NAG) and angiotensin converting enzyme (ACE) and urine microalbumin was assessed in this study to define the possible biofactor for detection of early diabetic nephropathy. Urinary enzyme activities of NAG and ACE and urine microalbumin of 24 h, serum ACE, and some other clinical features are investigated in 35 type 2 diabetic patients. Glycated hemoglobin (HbA1c), triglycerides, serum ACE, and urine NAG were significantly elevated in diabetic groups compared to the healthy controls. There was no relation between urine NAG and microalbuminuria except in the group of diabetic patients which had urine NAG activity upper than 25 IU/ml; there was a correlation between urine NAG and serum ACE. We may conclude that before the finding of microalbumin in urine, the elevated urine NAG, as an early indicator of renal damage, is associated with serum ACE which is related to kidney vascular microangiopathies.

Temporal changes in urinary levels of cadmium, N-acetyl-β-d-glucosaminidase and β2-microglobulin in individuals in a cadmium-contaminated area

Cadmium (Cd) is a metal that is toxic to renal tubules. If renal tubules are damaged by Cd, urinary excretion of N-acetyl-β-D-glucosaminidase (NAG) and beta 2-microglobulin (β2-MG) increases. The aim of this study was to describe the changing patterns of urinary Cd, NAG, and β2-MG levels over a 3-year period in individuals living in a Cd-contaminated area. This follow-up study included 191 residents (65.6±9.3 years) who were living in the vicinity of a copper refinery. Urinary levels of Cd, NAG activity, and β2-MG levels were measured, and their determinants and changing patterns were analyzed statistically. The natural logarithm of urinary Cd levels decreased significantly over time. Sex and intake of locally cultivated rice were significant determinants of urinary Cd concentration. Urinary NAG activity decreased over time. Age and urinary Cd concentration were significant determinants of urinary NAG activity in subjects with urinary Cd concentrations >5μg/g creatinine. In subjects whose urinary Cd concentrations were >2μg/g creatinine, diabetes was found to be a significant risk factor for high urinary NAG activity. The slope for temporal changes in urinary β2-MG levels was negative in subjects whose urinary Cd levels were <2μg/g creatinine but was positive in those whose urinary Cd levels were 2–5μg/g creatinine or >5μg/g creatinine. The urinary β2-MG levels found in individuals whose urinary Cd levels were >2μg/g creatinine suggest that previous Cd-induced renal tubular damage had occurred.