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Biomedical subjects

R G Price

Publications and source records attributed to R G Price.

117 records · Page 7Linked to original sources
PubMed1967

Rat-urine glycosidases and kidney damage.

1. The activities of beta-galactosidase, beta-glucosidase, beta-glucuronidase and N-acetyl, beta-glucosaminidase were estimated in normal and pathological rat urine, with 4-methylumbelliferyl glycosides as substrates. 2. Kidney damage induced by injections of uranium nitrate, mercuric chloride, potassium dichromate or 4-nitrophenylarsonic acid causes a marked increase in the urinary excretion of all four enzymes. 3. The rise in beta-glucosidase activity was associated with the appearance of a new urinary enzyme species, which was examined by starch-gel electrophoresis, DEAE-cellulose chromatography and filtration on Sephadex G-75 and G-200. 4. This enzyme appears to be identical with its counterpart in the kidney, and it is suggested that it arises in the urine as a result of renal tubular breakdown. 5. The other glycosidases examined also show some physical similarities to the corresponding enzymes of the rat kidney.

Animals↗
PubMed1967

The cellular distribution of some rat-kidney glycosidases.

1. Free and total activities of beta-glucosidase, beta-galactosidase, N-acetyl-beta-glucosaminidase and beta-glucuronidase have been determined fluorimetrically in five subcellular fractions of rat kidney. 2. The beta-glucosidase activity appeared in the soluble fraction, beta-glucuronidase had the distribution pattern of a lysosomal enzyme, and both beta-galactosidase and N-acetyl-beta-glucosaminidase had bimodal distributions. 3. Two types of beta-galactosidase activity were found: a sedimentable type, having optimum pH3.7, mol.wt. about 80000 and slow electrophoretic mobility at pH7.0 in starch gel; and a soluble type of much faster mobility, having optimum pH5.5-6.5 and mol.wt. about 40000. 4. Evidence is presented that the beta-glucosidase and the soluble type of beta-galactosidase are the same enzyme. 5. Most of the N-acetyl-beta-glucosaminidase activity was in the lysosome-rich fractions, but a significant proportion occurred in the microsomal fraction in a non-latent form. 6. The use of beta-galactosidase and N-acetyl-beta-glucosaminidase as lysosomal marker enzymes is complicated by the possible presence of multiple forms, but this limitation does not apply to beta-glucuronidase in the rat kidney.

Animals↗
PubMedDate not supplied

Effect of D-penicillamine on glomerular basement membrane, urinary N-acetyl-beta-D-glucosaminidase and protein excretion in rats.

The administration of D-penicillamine (450 mg/kg) to young rats resulted in an immediate increase in urinary NAG and volume, as well as mild proteinuria of a predominently low molecular weight type. Doses less than 400 mg/kg failed to alter the urinary profile. Analysis of glomerular basement membrane prepared from rats injected with D-penicillamine (450 mg/kg) failed to show any abnormalities in amino acid and sugar composition. In contrast, glomerular basement membrane prepared from D-penicillamine injected rats was more soluble than membrane prepared from normal rats in SDS and 2-mercaptoethanol. The solubilised components of the membrane were resolved on SDS-polyacrylamide gel electrophoresis. An increase in the low molecular weight, and a concomitant fall in the higher molecular weight components present in the membrane was demonstrated. D-penicillamine therefore affects glomerular basement membrane directly in young rats, possibly by interfering with cross-link formation. These studies may provide a further basis for the study of D-penicillamine toxicity in man.

Acetylglucosaminidase↗
PubMedDate not supplied

Polycystin expression during embryonic development of human kidney in adult tissues and ADPKD tissue.

Normal renal tissue, ranging from 8 weeks' gestation to full term to adult, was probed with polyclonal antibodies raised to peptide epitopes within the translated PKD1 gene sequence. Three antibodies were studied, all of which gave similar results. Renal tissue from patients with autosomal dominant polycystic kidney disease (ADPKD) and samples from normal adult liver, heart, brain, skeletal muscle and lymph node were also studied. Tissue staining demonstrated that the pattern of polycystin expression changed with gestational age in normal kidney. Whereas the precursors to the renal excretory unit were stained at 12 weeks, and the proximal and distal convoluted tubules stained to differing degrees throughout development, the glomeruli were poorly stained until full term and also in the adult. Extrarenal tissue stained in both adult and juvenile samples, with the exception of lymph node, which remained unstained. The intensity of polycystin staining increased in ADPKD renal tissue. The widespread distribution of polycystin was consistent with the systemic nature of ADPKD and the role of epithelial cells in the disease.

Adult↗
PubMedDate not supplied

Analysis of herbicides: demonstration of the utility of enzyme immunoassay verification by HPLC.

Evidence has accumulated that herbicides in the environment present a significant health hazard to the population. Therefore, the levels of heavily used substances such as atrazine and simazine and their metabolites need to be regularly assessed. The objective was to develop a rapid and simple tube ELISA procedure suitable for use in field studies and non-specialized laboratories. The antisera used were polyclonal antibodies raised in sheep against atrazine or simazine amido caproic acid conjugated to bovine serum albumin. The antibodies were first used to construct a two-step competitive ELISA procedure in 96-well microtitre plates. The 96-well format was then adapted to a coated-tube enzyme immunoassay, by immobilization of hapten-gelatine conjugates on polystyrene tubes. This enabled the colour to be read using a basic spectrophotometer. Soil samples were collected from agricultural and non-agricultural sites in Poland. Atrazine and simazine were extracted by liquid extraction from soil and assayed by tube ELISA. In addition, the samples were extracted by solid-phase extraction before analysis by HPLC. The immunoassays and chemical analysis were carried out by different individuals who were unaware of each other's results, which were then compared at the end of the study. Correlation of the two methods was excellent, with R=98.7 and 81.3 for atrazine and simazine, respectively. The immunoassay yielded the same order of results without having to perform solid-phase extraction before analysis. The study has demonstrated that the simple antigen-coated tube assay provides a cost-effective and valuable screening test. Comparison with the more elaborate, heavily labour-intensive HPLC analysis demonstrated that the results obtained by the simpler enzyme-immunoassay tests were within the same order.

Atrazine↗
PubMedDate not supplied

Early markers of nephrotoxicity: detection of children at risk from environmental pollution.

The current investigation is the largest to date concerned with the assessment of the value of different urinary biomarkers to detect nephrotoxic effects in children exposed to cadmium and lead. A battery of tests which had proved valuable in previous studies on men and women where used, together with a number of more recently developed biomarkers. No significant effect of sex and age were found but the location of the children (site) was important. The results indicated that there might have been variability in either the assay procedures or sample handling between the different sites. A small group of tests were found to be elevated following toxic exposure and should be used in future studies. However, there was considerable variation in the degree of exposure amongst the control groups from different countries and in the test groups. This made pooling of the data difficult but the study does highlight the way forward and demonstrates that children can be at risk from environmental exposure to toxins at a lower level than is acceptable for adults.

Adolescent↗
PubMedDate not supplied

Urinary N-acetyl-beta-D-glucosaminidase excretion in insulin-dependent diabetes mellitus: relation to microalbuminuria, retinopathy and glycaemic control.

N-Acetyl-beta-D-glucosaminidase (NAG) excretion was measured in early morning urine samples from 133 Albustix-negative, normotensive insulin-dependent diabetic patients and 89 non-diabetic controls. Urinary NAG activity was determined using a chromogenic substrate, 2 methoxy-4-(2'-nitrovinyl)-phenyl 2-acetamido-3-deoxy-beta-D-glucopyranoside, and expressed as mumol MNP released/hour/mmol of creatinine. Overall, diabetic patients were found to have a significantly elevated mean urinary NAG activity (p less than 0.01) compared to controls. Within the diabetic patients urinary NAG activity was significantly elevated in patients with either microalbuminuria (p less than 0.001) or "poor" glycaemic control (p less than 0.001), but not in those with retinopathy (p = 0.117). Three-way analysis of variance revealed that the relationship of raised urinary NAG to microalbuminuria and "poor" glycaemic control were statistically independent. Elevated urinary NAG excretion in insulin-dependent diabetes mellitus appears to be associated with early diabetic nephropathy and poor long-term glycaemic control.

Acetylglucosaminidase↗