Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Low molecular weight proteins are of interest in children because their increased urinary excretion is a sign of renal tubular disease and their increased plasma concentration is inversely related to glomerular filtration rate. These proteins include beta 2-microglobulin (B2M), retinol-binding protein (RBP), alpha 1-microglobulin (A1M) and lysozyme. B2M is unstable in acid urine, in contrast to RBP and A1M which are more stable. Any increase in the urinary excretion of B2M or RBP is highly specific for tubular disease, whereas increased excretion of A1M may be seen with glomerular proteinuria. Areas of clinical application include tubular and glomerular diseases, detection of drug toxicity, reflux nephropathy, birth asphyxia and insulin-dependent diabetes mellitus. Methods of sample collection and analysis of these proteins are discussed.
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PMID:Low molecular weight proteins in children with renal disease. 128 25

Biochemical markers of kidney damage were examined in 52 male stainless steel welders (manual metal arc welding) exposed to chromium and nickel. No difference was found in the mean urinary excretion of total proteins, albumin, protein 1, transferrin, retinol-binding protein, lactate dehydrogenase, lysozyme, or beta-N-acetylglucosaminidase in a comparison with matched referents. Beta 2-microglobulin was slightly increased in those welders with a urinary chromium concentration of greater than 64.5 nmol.mmol-1 creatinine. The prevalences of abnormal values did not differ from those observed in the reference group. No correlation was found between the concentrations of chromium or nickel in urine and that of proteins or enzymes. No consistent or clinically significant renal impairment was revealed among the stainless steel welders exposed to a chromium air concentration slightly above the current threshold limit value of the American Conference of Governmental Industrial Hygienists for water-soluble hexavalent chromium compounds (50 micrograms.m-3).
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PMID:Lack of renal changes in stainless steel welders exposed to chromium and nickel. 141 68

A cross-sectional study was conducted to determine whether exposure to hydrocarbons in a shoe factory may produce renal effects that can be detected by determination of the urinary excretion of proteins and enzymes. The study population included 59 women who had been exposed to petroleum naphtha and toluene and 24 age-matched control women. The time-weighted average exposure to petroleum naphtha, toluene and ethylacetate was 1,619,81 and 160 mg/m3, respectively. The integrity of the renal structures or functions was assessed by measuring the urinary excretion of total protein, beta 2-microglobulin, retinol-binding protein, albumin, transferrin, lysozyme, lactate dehydrogenase and beta-N-acetylglucosaminidase (NAG). The only parameter that was significantly influenced by hydrocarbon exposure was the urinary activity of beta-N-acetylglucosaminidase. Although the health significance of this renal change, which was not accompanied by changes in the urinary excretion of low- or high-molecular-weight proteins, is unclear, the results of the present study are in agreement with our previous observations suggesting that long-term moderate exposure to solvents does not entail a significant risk for the development of nephrotoxicity.
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PMID:Urinary excretion of proteins and enzymes in workers exposed to hydrocarbons in a shoe factory. 176 14

The value of various protein and enzyme markers for the assessment of early nephrotoxicity of tobramycin was studied in 18 patients with febrile infection. The renal clearance of creatinine and the excretion of the following protein and enzyme markers were measured on the first and the last day of the 5-8 day treatment period: albumin, N-acetyl-beta-D-glucosaminidase (NAG), beta 2-microglobulin, alpha-amylase, lysozyme and retinol-binding protein (RBP). Diurnal excretions of beta 2-microglobulin, lysozyme and RBP, all markers of tubular dysfunction, were already increased on the first treatment day, compared to similar control patients treated with non-aminoglycoside antibiotics and reference values of our laboratory. The excretion of NAG, an enzyme released from tubular cell lysosomes, was not increased initially, but on the last treatment day it was increased most consistently of all the markers studied. Glomerular filtration rate was halved in 5 of the patients. The results suggest that the initial increase in beta 2-microglobulin, lysozyme and RBP excretion is a result of an early tubular transfer block by tobramycin, whereas the late increase in NAG excretion probably reflects the progress of tubular cell damage during the course of aminoglycoside therapy.
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PMID:Nephrotoxicity of tobramycin. Value of examining various protein and enzyme markers. 187 78

The selectivity of the renal reabsorption of proteins has been investigated by competition experiments in conscious rats. The animals were intravenously injected with increasing doses of proteins over a wide range of net charge and size, including lysozyme, cytochrome C, metallothionein, beta 2-microglobulin, retinol-binding protein, albumin and IgG. The urinary excretion of exogenous proteins injected concomitantly (human beta 2-microglobulin, retinol-binding protein, albumin and/or egg white lysozyme depending on the experiment) and of rat beta 2-microglobulin, albumin and IgG was determined with specific immunoassays. The results show that low molecular weight cationic proteins and low or high molecular weight anionic proteins can increase each other's urinary excretion. Several observations strongly suggest that these effects result from a competitive inhibition of renal uptake. The phenomenon is dose-related in most cases and, as evidenced by cytochrome C injection, transient, reproducible and saturable. In addition, the injected proteins induce a tubular type proteinuria irrespective of their net charge and size. In the case of cationic proteins, this finding excludes the possibility of an enhanced glomerular permeability due to a partial neutralization of the glomerular polyanion which, as demonstrated with protamine sulfate, entails a glomerular type proteinuria. These quantitative data on the mutual inhibition of renal uptake of a wide spectrum of specific proteins lead us to challenge the concept of charge- and size-selective tubular reabsorption of proteins, and to postulate that proteins filtered through the glomeruli are taken up by common tubular endocytotic sites irrespectively of their physicochemical features. As demonstrated by the ability of beta 2-microglobulin and IgG to inhibit the uptake of lysozyme, the affinity of a protein for reabsorption sites is not simply related to its size and net positive charge. Evidence is also presented that proteins, when administered intravenously at high doses, induce a lysosomal enzymuria most likely reflecting a stimulated exocytosis.
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PMID:The renal uptake of proteins: a nonselective process in conscious rats. 246 Jun 61

Biochemical markers of kidney damage were examined in 37 female workers exposed to an average concentration of 225 mg/m3 of styrene. The concentration of mandelic acid in urine was on the average 759 mg/g creatinine. The mean duration of employment of the exposed subjects was 11 years. The results were compared to those obtained in 35 control female workers matched for age and a number of demographic and lifestyle factors and with no history of exposure to organic solvents. No difference was found in the urinary excretion of albumin, beta 2-microglobulin, retinol-binding protein, total proteins, glucose, lysozyme, lactate dehydrogenase and beta-N-acetyl-D-glucosaminidase. The present study provides thus further evidence that exposure to styrene at the current TLV (215 mg/m3) does not entail any detectable risk for the renal function.
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PMID:Lack of nephrotoxicity of styrene at current TLV level (50 ppm). 274 72

Asymptomatic low molecular weight proteinuria, a disease recently reported by Suzuki et al. [1985], was found in five boys, two pairs of brothers and a sporadic patient aged 3 to 11 years. Their urinary proteins contained 56% to 67% of proteins of less than 40,000 mol wt, defined as low molecular weight proteins by Suzuki et al. [1985], an indication that proximal tubular reabsorption of these proteins is impaired in these patients. Their glomerular function tests and intravenous urography were normal. An attempt was made to identify urinary low molecular weight proteins in these patients, using Western blotting analysis of the protein bands separated by sodium dodecylsulfate polyacrylamide gel electrophoresis. All five proteins tested were detected: alpha 1-acid glycoprotein (mol wt 44,000), alpha 1-microglobulin (mol wt 33,000), retinol-binding protein (mol wt 21,000), lysozyme (mol wt 14,000), and beta 2-microglobulin (mol wt 11,800). The latter two proteins had been identified in the disease by other means by Suzuki et al. [1985], while the other three were newly identified. Light microscopic studies of renal biopsy specimens from these patients revealed in three of four patients tested focal global or segmental glomerular sclerosis with scattered intratubular casts and focal tubular atrophy. Immunofluorescence staining of the renal biopsy specimens for the five proteins revealed some in the lumens of the proximal tubules and in the casts in the distal or collecting tubules, while only retinol-binding protein was found in the epithelial cytoplasm of the proximal tubules.
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PMID:Asymptomatic low molecular weight proteinuria: studies in five patients. 330 34

To study the effect of gentamicin on the renal uptake of proteins, Sprague-Dawley female rats were intravenously injected with solutions containing unlabeled human beta 2-microglobulin (beta 2-m), retinol-binding protein, and increasing amounts of gentamicin (from 0.063 up to 31.5 mg/kg). The concentrations of human proteins and that of endogenous beta 2-m, albumin, and IgG in the urine collected during the 2 hr following the injection were determined by immunoassays. Gentamicin transiently increased the urinary excretion of rat and human beta 2-m in a dose-dependent manner. The mean relative increase of rat beta 2-m excretion ranged from 2 at a gentamicin dose of 0.06 mg/kg up to 500 at a gentamicin dose of 31.5 mg/kg. By contrast, the urinary excretion of other proteins was only increased by a factor of 2 to 5 at the highest dose of gentamicin. The relative increase of the urinary excretion of proteins was positively correlated with the fractional reabsorption of the proteins by the rat kidney. The inhibitory effect of gentamicin on the renal uptake of protein was very similar to that observed in rats injected with polycationic proteins like lysozyme and cytochrome C. These observations, combined with the fact that gentamicin, like proteins, enters the tubular cell by adsorptive endocytosis, strongly suggest that this drug competes with proteins for common binding sites on the apical tubular membrane and for subsequent endocytosis. Furthermore, the iv injection of large amounts of gentamicin and polycationic proteins induces a lysosomal enzymuria which very likely is a manifestation of an increased exocytosis.
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PMID:Effects of gentamicin on the renal uptake of endogenous and exogenous protein in conscious rats. 352 31

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 creatine, beta 2-microglobulin, alpha 1-anti-trypsin 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-microglubulin may be used together to assess cadmium exposure and toxicity.
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PMID:Biological indicators of cadmium exposure and toxicity. 352 14

Levels of retinol-binding protein (RBP) and transthyretin (TTR) were determined in rat maternal livers, placenta, yolk sac, whole fetuses and fetal livers at different stages of gestation. Yolk sac concentrations of RBP and TTR expressed as micrograms per mg protein were three- to fivefold higher than liver values. TTR (moles) in the whole fetus was higher than RBP at all stages of gestation. Fetal hepatic RBP concentration was relatively constant throughout gestation, where fetal hepatic TTR concentration was low until close to parturition. RBP was observed in fetal microsomes at 12 d gestation. Incorporation of labeled amino acids into both RBP and TTR in vitro was observed in the yolk sac. In the 20-d fetal liver, incorporation to RBP and TTR was observed, whereas at 14 d gestation, incorporation only to RBP was observed. A small amount of synthesis of both proteins was also observed in the placenta. In the fetal circulation at 20-21 d gestation, no TTR-RBP complex was observed; instead a broad peak of RBP was found eluting at 20,000-40,000 daltons on gel chromatography. Incubation of fetal serum with maternal TTR resulted in an RBP peak eluting with an Mr of approximately 40,000. Treatment of the fetal serum with either lysozyme, neuraminidase or endoglycosidase H resulted in a 20,000 dalton RBP peak and following incubation with maternal TTR, a 70,000 dalton RBP-TTR complex was formed. Yolk sac, fetal liver and amniotic fluid on gel filtration exhibited a 40,000-20,000 dalton RBP peak. It is suggested that retinol transport in the fetus may involve RBP and TTR synthesized in the yolk sac as well as in fetal tissue.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Synthesis of retinol-binding protein and transthyretin in yolk sac and fetus in the rat. 357 57


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