Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.2.1.17 (lysozyme)
21,489 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The increasing environmental and occupational exposure of populations to cadmium creates the need for biological indicators of cadmium exposure and toxicity. The advantages and disadvantages of monitoring blood cadmium, urinary, fecal, hair, and tissue cadmium, serum creatinine, beta 2-microglobulin, alpha 1-antitrypsin and other proteins, and urinary amino acids, enzymes, total proteins, glucose, beta 2-microglobulin, retinol-binding protein, lysozyme, and metallothionein are discussed. It is concluded that urinary cadmium, metallothionein and beta 2-microglobulin may be used together to assess cadmium exposure and toxicity.
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PMID:Biological indicators of cadmium exposure and toxicity. 636 18

In patients on regular dialysis treatment, uremic symptoms (anemia, osteopathy, myopathy, neuropathy, and disorders of carbohydrate, fat, and protein metabolism) may be partly due to an accumulation of low molecular weight (MW) proteins (10,000 to 60,000 daltons). We tested this hypothesis using membranes with a higher permeability than conventional Cuprophan membranes. The primary aim of the study was to test the cutoff of various hemofilters (Cuprophan [Highflux], polyamide [FH 20], cellulose acetate [Duoflux], and polyacrylonitrile [Hospal RP 7 + 8 and Asahi PAN]) under in vivo conditions. In addition the effects of hemofiltration on plasma low molecular weight protein concentrations, polyneuropathy, and autonomic insufficiency were also tested in a long-term (six-month) study using the membrane with the highest cutoff and most constant sieving coefficient, i.e., Highflux. Low MW proteins with a defined MW were used as marker substances. Sieving coefficients of beta 2-microglobulin, lysozyme, retinol-binding protein, alpha 1-glycoprotein, alpha 1-antitrypsin, prealbumin, albumin, and transferrin were determined during a four-hour hemofiltration (20 L ultrafiltrate). Proteins were analyzed using an immunodiffusion technique. In the long-term study, motor nerve conduction velocity, the Schellong test, and Valsalva maneuver were tested prior to and three and six months after hemofiltration therapy. Highflux, Duoflux, and FH 202 membranes were permeable to proteins with molecular weights up to 15,000 daltons, and the Highflux module had the most constant sieving coefficient during hemofiltration. In the six-month hemofiltration study with the Highflux filter, plasma beta 2-microglobulin and lysozyme decreased significantly as expected. Parameters of polyneuropathy and autonomic insufficiency were slightly improved.
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PMID:Elimination of low molecular weight proteins during hemofiltration. 681 37

Fifteen various serum and urine parameters were evaluated as indicators of renal alterations induced by lead in 82 male workers of a battery plant chronically exposed to lead (median of blood lead concentration: 2.03 mumol/l). The control group comprised 44 non-exposed healthy volunteers (0.34 mumol/l). High-molecular-mass proteins (transferrin, immunoglobulin G (IgG), (albumin)) were determined in urine as markers of glomerular integrity; low-molecular-weight proteins and parenchymal enzymes (alpha 1-microglobulin, beta 2-microglobulin, retinol-binding protein, lysozyme, ribonuclease, N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase (AAP), alkaline phosphatase (AP), gamma-glutamyltransferase (GGT)) as indicators of changes in the proximal tubule; Tamm-Horsfall glycoprotein and kallikrein as markers of the distal tubule. There was a positive correlation between tubular indicators and blood lead concentration as well as the erythrocyte protoporphyrin (EPP). About 30% of the lead-exposed workers showed an increased excretion of alpha 1-microglobulin, NAG, ribonuclease, and/or Tamm-Horsfall protein, whereas the glomerular indicators remained unchanged. The combined determination of NAG and alpha 1-microglobulin in urine could be helpful in the early detection of lead-induced changes in the nephron.
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PMID:Changed excretion of urinary proteins and enzymes by chronic exposure to lead. 752 73

We tested the diagnostic sensitivity of various urinary analytes for detecting cadmium-induced nephropathy at an early stage. We investigated 73 healthy persons (control group 1) and individuals exposed to cadmium, either environmentally (n = 36, risk group 2) or occupationally (n = 62, exposed group 3). All data were related to limits of the central 95% reference intervals of the control group. The serum creatinine and ribonuclease values, indicators of the glomerular filtration rate, were not different in the three groups. In the exposed persons (group 3), proximal tubular indicators (low-M(r) proteins lysozyme, ribonuclease, retinol-binding protein, and alpha 1-microglobulin) were more often increased than the glomerular indices (higher-M(r) proteins transferrin, IgG, and albumin). Both the low-M(r) proteins and tubular enzymes were differently altered in their excretion rates. Alanine aminopeptidase, alkaline phosphatase, and N-acetyl-beta-D-glucosaminidase increased even in the risk group 2. alpha 1-Microglobulin was increased in the exposed persons whose cadmium excretion was < 5 mumol/mol creatinine. The combined determination of alpha 1-microglobulin and N-acetyl-beta-D-glucosaminidase exceeded the corresponding upper reference limits in 30% of group 2 and 39% of group 3. We recommend screening for these two analytes to detect cadmium-induced renal dysfunction at an early stage.
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PMID:Urinary proteins and enzymes as early indicators of renal dysfunction in chronic exposure to cadmium. 848 64

1. Biochemical markers of kidney damage were examined in 14 male and 12 female workers highly exposed to soluble nickel compounds in a chemical plant. The results were compared to those obtained in 12 male and 12 female matched controls. 2. The concentration of nickel in urine of male and female workers averaged 5.0 and 10.3 micrograms g-1 creatinine, respectively. The mean duration of exposure in male and female workers was 25 and 15 years. 3. No difference was found in the mean urinary excretion of lactate dehydrogenase, albumin and transferrin in both sexes, total proteins, beta 2-microglobulin (beta 2-m) and retinol-binding protein (RBP) in males and lysozyme in females. Lysozyme and N-acetyl-beta-D-glucosaminidase (NAG) were increased in male and total proteins, beta 2-m, NAG and RBP in female exposed workers. Significant correlations between urinary concentrations of nickel on one side and that of beta 2-m in women (r = 0.462, P = 0.022) and men (r = 0.41, P = 0.018) and of NAG in men (r = 0.405, P = 0.019) on the other side were found in exposed subjects. 4. Results indicate adverse effects of soluble nickel compounds on the kidney tubular function. In agreement with literature data it seems that those effects occur only at high exposure levels.
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PMID:Biochemical renal changes in workers exposed to soluble nickel compounds. 820 11

Proteinuria is one of the bad prognostic indices in renal disease. This study compares the pattern of protein excretion in 10 patients with IgA nephropathy (IgAN), 10 patients with chronic glomerulonephritis approaching end-stage renal failure (ESRF) who still had proteinuria and 10 other patients with diabetic nephropathy (DN) with proteinuria but normal renal function. The pattern of proteinuria was analysed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), isoelectric focusing (IEF) and assayed for orosomucoid, alpha-1-microglobulin, retinol-binding protein, lysozyme, beta-2-microglobulin and N-acetyl-beta-D-glucosaminidase activity. Our data showed much similarity in the pattern of proteinuria between the DN and ESRF groups but significant differences with the IgAN group. The pattern of proteinuria in the IgAN group reflects glomerulonephritis whereas the similar pattern between the ESRF and DN groups may reflect hyperfiltration as well as tubular injury.
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PMID:Pattern of proteinuria in tubular injury and glomerular hyperfiltration. 939 12

Renal failure (RF) in multiple myeloma (MM) is considered an ominous complication even though, when timely therapy is started in patients with minimal damage, a high percentage of cases can achieve a regression. The evaluation of renal involvement usually relies on serum creatinine or its clearance, but these parameters have proved to be inadequate to identify initial damage. The aim of this study was to assess the role of the following urinary proteins in diagnosing renal impairment at an early stage: high-molecular-mass proteins (transferrin, IgG, albumin) as markers of glomerular damage, and low-molecular-weight proteins and parenchymal enzymes [alpha(1)-acid glycoprotein (AGP), alpha(1)-microglobulin (alpha(1)M), retinol-binding protein (RBP), beta(2)-microglobulin (beta(2)M), lysozyme (LZ), and N-acetyl-beta-d-glucosaminidase (NAG)] as indicators of tubular disorder. Thirty MM patients (nine at disease onset and 21 previously treated) were included in the study. No correlation was found between the urinary proteins and the phase or the stage of the disease. By the Spearman test, Bence Jones proteinuria correlated significantly with the 24 h proteinuria (p=0. 01) and beta(2)M (p=0.02), and weakly with the alpha(1)M. Serum creatinine concentrations and urea correlated with most of the analytes evaluated: RBP correlated well with urea (p=0.004) and creatinine (p=0.004); IgG (p=0.006) albumin (p=0.009), AGP (p=0.04), and NAG (p=0.02) correlated with serum creatinine. Significant statistical correlation was found between all the analytes except LZ and the creatinine clearance. Twelve of the 30 MM patients (40%) showed abnormal values of urinary proteins. Four of these patients showed overt renal failure with significant modification of the serum parameters and of creatinine clearance, three showed an isolated decrease of creatinine clearance, and five did not present any alteration of serum or urinary parameters. This testifies to the utility of urinary proteins in highlighting renal damage even in cases where the customary serum indicators of renal disorder are normal. In conclusion, our results demonstrate that AGP, RBP, NAG, transferrin, and IgG are good indicators of renal damage. They do not correlate with the severity of the disease, but they seem to be helpful in identifying a subset of patients with initial renal dysfunction.
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PMID:Assessment of renal function in patients with multiple myeloma: the role of urinary proteins. 1046 Mar 51

Plasma retinol-binding protein (RBP) combined with vitamin A (retinol) is partially filtered through the glomerulus and then absorbed by proximal tubule cells, leading to recycling of retinol to the circulation. Recently, it was shown that reabsorption of RBP-retinol complexes by proximal tubule cells is mediated by megalin (gp 330), an apical endocytic receptor. It was proposed that RBP is transported by megalin to lysosomes, where it is degraded, thus liberating retinol, which then combines with newly synthesized RBP to be secreted into the bloodstream. This study shows that passage of RBP through immortalized rat renal proximal tubule (IRPT) cells occurs by transcytosis after megalin-mediated endocytosis, which provides an alternative pathway for recycling of retinol. IRPT cells cultured as polarized monolayers with tight junctions were used on permeable filters in the upper chamber of dual-chambered devices, with megalin expression exclusively on the upper surface. After addition of RBP to the upper chamber and incubation at 37 degrees C, intact RBP was found in fluids that were collected from the lower chamber. In contrast, control substances (mannitol, lysozyme, albumin, and glutathione-S-transferase) were not appreciably transported across IRPT cells, indicating that passage of RBP was by transcytosis and not by paracellular leakage. Confocal microscopy analysis of IRPT cells after addition of RBP to the upper chamber revealed RBP-containing granules at the apical membrane, subapically, and also at basolateral membranes. When RBP was added to IRPT cells together with megalin competitors, the amount of transcytosed RBP was markedly reduced. We also found that some RBP was internalized and degraded by IRPT cells, but this process was not appreciably affected by megalin competitors, indicating that RBP endocytosed by megalin was not transported to lysosomes and degraded but rather transcytosed across IRPT cells.
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PMID:Transcytosis of retinol-binding protein across renal proximal tubule cells after megalin (gp 330)-mediated endocytosis. 1127 24

This paper reports the results of a study that aimed to assess whether liver functionality defined by liver activity index (LAI) is associated with inflammatory and immune parameters in blood and milk. LAI is an index including the average blood levels of albumin, lipoproteins and retinol-binding protein measured three times in the first month of lactation (at 5, 15 and 30 days in milk). The aim was to assess the relationship of this index with blood and udder immune and inflammatory status as a means of identifying as early as possible cows at risk of disease. The research was carried out using 10 multiparous Italian-Friesian dairy cows of average genetic merit. Cows were retrospectively ranked in three groups according the LAI level. Blood samplings were performed at different intervals before and after calving; quarter milk samples were taken only after calving with the same schedule as blood samples. Leucocytes, oxidative burst, blood lysozyme and N-acetyl-beta-d-glucosaminidase (NAGase) curves showed large overlapping among the three LAI group curves during the follow-up period. Four blood (complement, sialic acid, haptoglobin and reactive oxygen metabolites) and three milk (somatic cell count, lysozyme and NAGase) parameters showed larger and more consistent differences among LAI groups. Complement showed higher values and sialic acid showed lower values in high LAI group when compared with the other two LAI groups. Two other markers of inflammatory status (haptoglobin and reactive oxygen metabolites) showed the lowest values in high LAI cows. A consistent and significant reduction of milk NAGase and milk lysozyme in high LAI group was observed. The results suggest that cows with the highest liver functionality index have also the highest levels of some immune markers and the lowest levels for inflammatory markers at blood (already before calving) and mammary levels. Finally, cows with low LAI index, being more susceptible to metabolic and infectious diseases, should be carefully monitored to identify as early as possible the development of a disease.
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PMID:Blood and milk immune and inflammatory profiles in periparturient dairy cows showing a different liver activity index. 2057 69

Computing the ligand-protein binding affinity (or the Gibbs free energy) with chemical accuracy has long been a challenge for which many methods/approaches have been developed and refined with various successful applications. False positives and, even more harmful, false negatives have been and still are a common occurrence in practical applications. Inevitable in all approaches are the errors in the force field parameters we obtain from quantum mechanical computation and/or empirical fittings for the intra- and inter-molecular interactions. These errors propagate to the final results of the computed binding affinities even if we were able to perfectly implement the statistical mechanics of all the processes relevant to a given problem. And they are actually amplified to various degrees even in the mature, sophisticated computational approaches. In particular, the free energy perturbation (alchemical) approaches amplify the errors in the force field parameters because they rely on extracting the small differences between similarly large numbers. In this paper, we develop a hybrid steered molecular dynamics (hSMD) approach to the difficult binding problems of a ligand buried deep inside a protein. Sampling the transition along a physical (not alchemical) dissociation path of opening up the binding cavity---pulling out the ligand---closing back the cavity, we can avoid the problem of error amplifications by not relying on small differences between similar numbers. We tested this new form of hSMD on retinol inside cellular retinol-binding protein 1 and three cases of a ligand (a benzylacetate, a 2-nitrothiophene, and a benzene) inside a T4 lysozyme L99A/M102Q(H) double mutant. In all cases, we obtained binding free energies in close agreement with the experimentally measured values. This indicates that the force field parameters we employed are accurate and that hSMD (a brute force, unsophisticated approach) is free from the problem of error amplification suffered by many sophisticated approaches in the literature.
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PMID:Computing the binding affinity of a ligand buried deep inside a protein with the hybrid steered molecular dynamics. 2803 50


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