Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022672 (acute tubular necrosis)
 2,175 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Three urinary lysosomal enzymes, beta-glucuronidase (beta-Gluc), beta-galactosidase (beta-Gal) and N-acetyl-beta-D-glucosaminidase (NAG), were measured in twenty-one renal allograft recipients to evaluate their role in the diagnosis and prediction of rejection episodes, and in the prediction of eventual graft outcome. A fluorometric assay using methylumbelliferone substrates was used to measure the three enzymes in morning urine samples and enzyme activity was defined in terms of urine creatinine concentration. Urinary NAG levels increased significantly in 13/16 first rejection episodes and 4/4 instances of acute tubular necrosis and graft infarction. In 5 of the 16 first rejection episodes the NAG was predictive of the rejection. NAG was not useful in diagnosing second or subsequent rejections and beta-Gluc and beta-Gal were of little value in assessing any component of renal transplant pathology. As a prognostic index of eventual graft outcome, the peak urinary NAG was particularly encouraging. It correlated strongly with deterioration in graft function as time passed such that only 2/10 patients with peak NAG greater than 1400 Units had normal serum creatinines at 6 months post transplantation. Conversely 4/4 patients with peak NAG levels less than 700 Units had normal serum creatinine at that time. In our series the measurement of urinary NAG was a useful adjunct to the diagnosis of first rejections but appears to be more valuable in predicting graft outcome.
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PMID:Urinary lysosomal enzyme excretion after renal allotransplantation. 10 10

Male volunteers were infused with L-arginine dextran and Haemaccel. Arginine (0.5 g/kg body weight infused over 30 min) resulted in transient highly significant increases in urinary albumin (p less than 0.001), beta 2-microglobulin (p less than 0.001) and N-acetyl-beta-D-glucosaminidase [NAG] (p less than 0.001). These effects lasted less than 120 min. Dextran 40 and 70 (500 ml infused over 2 h) did not affect urinary albumin, beta 2-microglobulin or NAG excretion. Haemaccel (8 ml/kg body weight infused over 2 h) resulted in significant increases in urinary albumin (p less than 0.05) and beta 2-microglobulin (p less than 0.01) during the second hour of the infusion. It also caused a biphasic increase in urinary NAG excretion, the initial peak (p less than 0.05) coinciding with the peak of albumin and beta 2-microglobulin excretion. The second peak which was more defined (p less than 0.01) occurred 21-24 h after the beginning of the infusion. Neither arginine or Haemaccel have been reported to be nephrotoxic whereas dextran infusions are a well recognised cause of acute tubular necrosis. These data indicate that increases in urinary beta 2-microglobulin and NAG are not always reliable indicators of nephrotoxicity or renal tubular cell damage.
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PMID:The effects of arginine, dextran and Haemaccel infusions on urinary albumin, beta 2-microglobulin and N-acetyl-beta-D-glucosaminidase. 242 74

Traditional methods of noninvasively evaluating patients for renal injury do not accomplish the following tasks: reliably distinguish potentially treatable forms of acute renal failure from acute tubular necrosis; provide a sensitive indicator of early allograft rejection in renal transplant recipients, particularly those in the pediatric age group; provide an early warning of incipient drug-induced nephrotoxicity; or serve as an adequate screening test for renal injury due to exposure to occupational or environmental toxins, especially heavy metals. Because of this, considerable effort has been devoted to the development of assays to satisfy these needs. Three approaches include measurement in the urine of low-molecular-weight plasma proteins such as beta 2-microglobulin; a variety of kidney-derived enzymes, such as L-alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase; and specific renal antigens using immunologic detection. The first two of these have not proved to be adequately sensitive or specific, complicated by the frequent loss of activity associated with the physicochemical characteristics of the urine or the presence of pyuria. Despite this, useful information has been obtained. In particular, assays of beta 2-microglobulin urinary excretion and retinol binding protein appear to have clinical utility that should be pursued. Recent experience with a monoclonal antibody-based assay for a unique proximal tubular antigen, the adenosine deaminase binding protein, suggests that a battery of such assays, each directed against an antigen localized to a particular segment of the nephron, may be particularly useful.
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PMID:Noninvasive renal diagnostic studies. 290 37

During the first month after bone marrow transplantation, approximately 15% of patients develop acute renal failure (ARF). This usually occurs in the setting of hepatic veno-occlusive disease (VOD). Prior clinical data have suggested that this form of ARF has a hemodynamic basis, analogous to the hepatorenal syndrome (HRS). If so, then proximal tubular injury would not be expected. To directly test this hypothesis, enzymuria (N-acetyl-beta-D-glucosaminidase [NAG]) was quantitated in the following groups of patients within the first 35 days after BMT: (1) VOD+ARF (serum creatinine level > 1.5 mg/dL; N = 10); (2) VOD with relatively normal renal function (serum creatinine level < 1.5 mg/dL; N = 11); and (3) patients without hepatic or renal complications (BMT controls; N = 12). For comparison, NAG was also quantitated in the following groups of non-BMT patients: (1) toxic/ischemic acute tubular necrosis (ATN) (N = 10); (2) jaundice without azotemia (N = 5); and (3) HRS (N = 6). Urine samples from eight healthy subjects established normal NAG concentrations (2.5 +/- 0.5 microU/mg urinary creatinine; mean +/- SE). All non-BMT patients with ATN had markedly elevated NAG levels (61 +/- 12; P < 0.001), validating the test as a marker of tubular damage. NAG concentrations were significantly elevated in all of the control BMT patients (24 +/- 3; P < 0.01), and the presence of VOD was associated with further striking increments (approximately 50 times normal). However, the degree of enzymuria was virtually identical for VOD patients with (125 +/- 27) and without (122 +/- 17) ARF. Jaundice in a non-BMT setting was associated with only mild NAG elevations (11 +/- 2). However, striking enzymuria was noted in all HRS patients (61 +/- 20), equaling the levels seen with ATN. The following conclusions were derived: (1) subclinical tubular injury, as defined by enzymuria, appears to be ubiquitous after BMT; (2) VOD dramatically increases the extent of enzymuria; (3) the degree of enzymuria in VOD patients is not correlated with renal dysfunction, implying that the associated ARF has a large hemodynamic component; and (4) HRS and ATN manifest comparable degrees of enzymuria, suggesting that substantial tubular damage exists in both of these forms of ARF.
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PMID:Marked enzymuria after bone marrow transplantation: a correlate of veno-occlusive disease-induced "hepatorenal syndrome". 874 94

Renal function in the early post-transplantation period depends largely on factors affecting the kidney prior to implantation. Function of the graft may be also disturbed by the most common complications of the early post-operative period such as acute graft rejection (AGR), acute tubular necrosis (ATN) and may be modified by nephrotoxic action of cyclosporine A (CsA). Evaluation of excretion of enzymes and low molecular weight proteins (LMWP) may help in the differentiation of these complications. Aim Comparison of the urinary excretion of markers of tubular injury in patients with AGR, ATN, or patients with stable graft function (SGF) was made and differences between groups and correlations between markers and cold ischemia time (CIT), warm ischemia time (WIT) and blood trough level of cyclosporine A (CsA0) were determined. Material and methods In 60 cadaveric renal allograft recipients in the early post-transplantation period urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and B isoenzyme (NAG-B), alanylaminopeptidase (AAP), gamma-glutamyltransferase (GGT), alpha and pi isoenzymes of glutathione S-transferase (alpha-GST, pi-GST), retinol binding protein (RBP) and beta2- microglobulin (beta2M), were analyzed. Results NAG and NAB-B activities were higher in ATN (P<0.05, P<0.01) and in AGR (P<0.005, P<0.02) than in SGF. Excretion of pi-GST was higher in AGR than in SGF (P<0.0002) or ATN (P<0.007). CIT and WIT in patients with ATN were higher (P<0.05) than in SGF group. In ATN patients, correlations of CIT with RBP (P<0.05) and pi-GST (P<0.05), and WIT with RBP (P<0.05), and pi-GST (P<0.001) were found. Conclusions High urinary NAG and NAG B excretion characterizes ATN and AGR patients. Evaluating urinary excretion of pi-GST may be helpful in differentiating AGR from ATN. However, taking into account ischemia time is necessary in interpreting the pi-GST value in early post transplant period.
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PMID:Enzymuria and low molecular weight protein excretion as the differentiating marker of complications in the early post kidney transplantation period. 1716 Apr 49