Search

Both sexes of F344 rats were gavaged with maximal tolerated doses of mercuric chloride for periods from 2 wk to up to 2 yr to investigate chronic nephrotoxicity and potential carcinogenicity. The toxicity of mercuric chloride was excessive after 2 wk of exposure to doses ranging from 1.25 to 20 mg/kg, compromising renal function by selectively destroying cells of the proximal tubules, and eliciting marked elevations in urinary biomarker enzymes diagnostic for acute renal tubule necrosis. In the 2-wk studies, urinary alkaline phosphatase and aspartate amino-transferase were most sensitive to renal mercury toxicity among a panel of six enzymes, exhibiting twofold increases above controls at the 5.0 mg/kg dose, before changes in the other enzymes occurred. Urinary lactate dehydrogenase was the most responsive enzyme, with up to 11-fold increases in activity above controls. In response to mercuric chloride exposure of 5.0 mg/kg for 2-6 mo, the greatest and most persistent increases in elevation of urinary enzyme activities were exhibited by alkaline phosphatase and gamma-glutamyl transferase, which increased two-to threefold above controls. At this interval, the maximal severity of the renal lesions in both sexes of rats was graded as minimal to mild. Beyond 6 mo none of the urinary enzymes measured in this study was adequate as biomarkers of nephrotoxicity, although the severity of the renal lesions had progressed. Mercury accumulated in a dose-related fashion primarily in the kidney, and to a lesser extent in the liver. The severity of the renal lesions was increased by continued exposure to mercuric chloride, as tissue concentrations of mercury rose in proportion to dose. Mercuric chloride treatment for 2 yr clearly exacerbated the severity of the spontaneous nephrotoxicity prevalent in aging F344 rats. The excessive mortality that occurred in the male rats was probably due to a combination of these factors. No renal tumors were detected in rats, possibly because the potential for their development was reduced; however, direct tissue contact with mercury induced squamous-cell papillomas of the forestomach in both sexes.

Urinary intestinal alkaline phosphatase (EC 3.1.3.1; IAP) is a marker of the S3 segment of the human kidney proximal tubule. An accurate enzyme-antigen immunoassay (EAIA) with a high-affinity specific monoclonal antibody (IAP250) developed for this marker has a detection limit below the lowest IAP activity found in urine samples of normal subjects. The intra- and interassay CVs were less than 5%. Mean analytical recovery of pure IAP added to urine was 102% (SD 6%), and the EAIA results correlated well with immunoreactivity (measured by a sandwich ELISA), suggesting that the EAIA detected all of the IAP in urine. In healthy individuals (ages 20-80 years) the IAP concentrations, expressed as urinary creatinine ratios, ranged from 0.1 to 2.0 U/g (5-95 percentiles) without major differences related to sex and age. Workers exposed to mercury, which affects the S3 segment, showed an increased IAP elimination; abusers of analgesics, which affect more distal parts of the nephron, did not. As opposed to currently measured markers, the EAIA offers easy, accurate, and precise measurement of early alterations in the S3 segment.

A new nonionic dimeric contrast medium (CM), iodixanol, was intravenously administered to 40 healthy male volunteers in doses of 0.3-1.2 g of iodine per kilogram of body weight, nonionic monomeric iopamidol and iopentol were administered to 20 others, and the renal effects were studied up to 120 hours after administration. Computed tomography of the kidneys was performed up to 80 hours after injection. Creatinine clearance as an index of the glomerular filtration rate was unchanged with all CM. Urine volume and osmolar clearance increased most with the monomeric CM. The proximal tubular brush border enzyme alkaline phosphatase increased with all CM. The lysosomal enzyme N-acetyl-beta-glucosaminidase increased more with the monomeric CM than with iodixanol. A persistent increased attenuation in the region of the cortex was observed with all CM. Attenuation returned to baseline within 80 hours, with the slowest decline with iodixanol. This delayed cortical enhancement did not correlate with the effects of the CM on the tubular enzyme excretion.

Intestinal-type alkaline phosphatase (IAP) is a specific and sensitive marker for alterations of the S3 segment of the human proximal tubule, the preferred part for several nephrotoxins. We studied IAP and other renal parameters in mercury-exposed workers and their controls. IAP excretion is clearly increased in the exposed workers, compared to other parameters, indicating that the determination of this enzyme can be a useful screening test of renal effects in occupational mercury exposure.

A sensitive and precise automated assay of urinary lactate dehydrogenase (EC 1.1.1.27), alkaline phosphatase (EC 3.1.3.1) and gamma-glutamyltransferase (EC 2.3.2.2) is described. For this purpose, we used a BM/Hitachi System 704 model and reagents for automated analysis of serum enzymes from Boehringer Mannheim. However, the schedules of enzyme chemistry parameters recorded by the autoanalyzer and the spectrophotometric calibration are reprogrammed to meet requirements deriving from urine adoption and to optimize the enzyme assay in this unusual medium.

We measured three renal tubular brush-border enzymes (lactate dehydrogenase, LDH, EC 1.1.1.27; gamma-glutamyltransferase, GGT, EC 2.3.2.2; and alkaline phosphatase, AP, EC 3.1.3.1) in morning urine samples from 48 healthy subjects to check whether different storage times and temperatures could modify enzyme concentrations. Short-term (24 h) storage time at room temperature or 4 degree C does not affect urinary enzyme activity. A few days of freezing, at -20 or -70 degrees C, dramatically lowers LDH and AP values; GGT is partially preserved only at -70 degrees C, if the sample has been previously centrifuged. Urinary enzymes investigated in this study are extremely labile at low temperatures.

Renal effects of the 2 non-ionic contrast media iopentol and iohexol were investigated and compared in a double-blind, randomized parallel study where 30 patients received iopentol, and 31 patients iohexol intravenously for abdominal CT. The dosage of contrast medium (350 mg I/ml) was 700 mg I/kg body weight. Only one patient (in the iohexol group) had an increase in serum creatinine of more than 50%. Iopentol and iohexol had no effects on the mean serum values of creatinine, urea, and beta 2-microglobulin (beta 2-MG) nor on creatinine clearance. The urinary excretion of albumin and beta 2-MG was also unchanged. The excretion of the proximal tubular enzymes alkaline phosphatase and N-acetyl-beta-glucosaminidase was increased. No significant difference between iopentol and iohexol was found.

A possible relationship between intestinal structure and function in the pathogenesis of psoriasis has recently brought about considerable interest. The purpose of this study was to evaluate the intestinal permeability in psoriatic patients by comparing it with healthy controls. 15 psoriatic patients and 15 healthy volunteers entered the study. Intestinal permeability was evaluated using the 51Cr-labeled EDTA absorption test. The 24-h urine excretion of 51Cr-EDTA from psoriatic patients was 2.46 +/- 0.81%. These results differed significantly from controls (1.95 +/- 0.36%; P less than 0.05). The difference in intestinal permeability between psoriatic patients and controls could be due to alterations in the small intestinal epithelium of psoriatics.

Urinary enzyme activities (N-acetyl-beta-D-glucosaminidase [NAG], alkaline phosphatase [ALP], leucine aminopeptidase [LAP], gamma-glutamyl transpeptidase [gamma-GTP]) were investigated to determine their clinical significance in diabetic nephropathy. There were correlations among ALP, LAP, and gamma-GTP, though no correlation existed between NAG and the other three enzymes. Activities of NAG isozymes (both A and B) were higher than in normal controls. It has been reported that NAG isozyme A might be associated with glomerular diseases, and isozyme B might be associated with proximal tubular damage. The results of our study suggest that NAG reflects lysosomal dysfunction of both glomerular and proximal tubular epithelial cells, which may be caused by poor glycemic control, and that ALP, LAP, and gamma-GTP reflect brush border damage of proximal tubules, which may be caused by diabetic nephropathy.

Experimental evidence suggests that the oxidative metabolites 2,3- and 2,5-dihydroxybenzoic acid (DIOH) may be responsible for the nephrotoxicity of salicylic acid (SAL). In the present study, enzymuria in conjunction with glucose (GLU) and protein (PRO) excretion were used as endpoints to compare the relative nephrotoxicity of SAL with 2,3- and 2,5-DIOH. In addition, the effect of age on enzymuria and GLU and PRO excretion following treatment with SAL or 2,3- and 2,5-DIOH was investigated because the elderly are at greater risk for SAL-induced nephrotoxicity. Three and 12-month male Fischer 344 rats were administered either no treatment, vehicle, SAL, 2,3-DIOH, or 2,5-DIOH at 500 mg/kg p.o. in 5 ml/kg corn oil/DMSO (5:1). Effects of these treatments on functional integrity of renal tissue was assessed from 0--72 h after dosing by measurement of urinary creatinine, GLU, and PRO, as well as excretion of proximal and distal tubular renal enzymes. Enzymes measured as indicators of proximal tubular damage were N-acetyl-beta-glucosaminidase (NAG), gamma glutamyltransferase (GGT), alanine aminotransferase (ALT), and alkaline phosphatase (AP), while urinary lactate dehydrogenase (LD) and aspartate aminotransferase (AST) were measured as indicators of distal tubular damage. In comparison to 3-month vehicle-treated rats, 2,3- and 2,5-DIOH caused a significant increase between 0-8 h in excretion of urinary GLU and activities of AST, NAG, and LD, with peak effects occurring between 4-8 h. Toxic effects of either metabolite were not evident beyond 24 h, and toxicity of 2,5-DIOH was significantly greater in comparison to 2,3-DIOH. SAL treatment resulted in similar effects on enzymuria as well as GLU and PRO excretion, but peak effects did not occur until 16-24 h, and often persisted until 72 h after dosing. Maximal enzymuria in response to SAL treatment was significantly greater in 12- vs. 3-month rats for AST, NAG, and LD. In response to 2,3-DIOH treatment, the maximal response was significantly greater in 12- vs. 3-month rats for LD and AST, and for NAG in response to 2,5-DIOH treatment. The results of this study suggest that both 2,3- and 2,5-DIOH are nephrotoxic metabolites of SAL, but implicate 2,5-DIOH as the more potent nephrotoxic metabolite. The relative lack of an age effect for 2,3- and 2,5-DIOH vs. SAL supports the hypothesis [2] that age-related differences in biotransformation of SAL, and not increased tissue sensitivity to 2,3- or 2,5-DIOH, contribute to the age-related increase in susceptibility to SAL-induced nephrotoxicity.

Seventeen patients were subjected to analysis of various renal functional parameters before and after extracorporeal shock wave lithotripsy (ESWL) for renal stones. Thirteen patients were observed at 2 weeks and 3 months. Glomerular filtration rate (GFR) was not influenced by ESWL as based on unchanged serum levels of creatinine, beta 2-microglobulin and creatinine clearance. A significant increase in urinary excretion of beta 2-microglobulin, N-acetyl-beta-glucosaminidase and alkaline phosphatase, with return to pre-treatment values within 4 to 5 days, reflected transient disturbances in proximal tubular function. Urinary albumin excretion was increased 0-24 h after ESWL. No significant alterations were observed in plasma renin activity or serum aldosterone due to ESWL. Serum lactic dehydrogenase remained significantly increased for 2 weeks. In addition, significant changes in several blood and urine parameters were caused by immersion in water and intravenous infusions during treatment and were not specifically due to ESWL.

There are several problems in measuring the activities of urinary enzymes, such as alkaline phosphatase (ALP), leucine aminopeptidase (LAP), and gamma-glutamyl transpeptidase (gamma-GTP) which are derived from renal tubulus. The purpose of the present study is to clarify the basic methodological problems in measuring these enzyme activities. Our results indicate that it is not necessary to dialyze urine when determining these three enzymes, except for alkaline phosphatase activity measured by the Kind-King method. Because of contamination of urine by bacteria and cell elements, the enzyme activity is influenced by centrifugal conditions that depend on time and speed. Our results propose that it is necessary, at least, to centrifuge at 3000 rpm for 10 minutes to obtain satisfactory data. Generally, a 24 hour urine sample instead of spot urine sample should be used for measuring the enzyme activity. However if correcting gamma-GTP activity by creatinine, even a spot urine sample may be used for clinical use.

Pregnant Sprague-Dawley rats were injected intraperitoneally with physiological saline solution (vehicle) or cadmium chloride (CdCl2) at 2.0 or 2.5 mg kg-1 on days 8, 10, 12 and 14 of gestation. On postnatal day (PND) 3, 12 or 49, the offspring were examined for 8- or 24-h urinary excretion of beta 2-microglobulin (beta 2-m), metallothionein (MT) and urinary activity of three proximal tubular enzymes: gammaglutamyl transferase (GGT), alkaline phosphatase (ALP) and N-acetyl-beta-glucosaminidase (NAG). Treatment with CdCl2 did not affect growth or survival of offspring. Significant decreases in the urinary excretion of GGT, ALP and NAG were observed on PND 3, at both doses. Exposure to 4 x 2.5 mg kg-1 resulted in functional deficit of the proximal tubule on PND 3, as evidenced by the significant increase in beta 2-m. Except for a slight but significant increase of beta 2-m in 49-day-old males, all the other urinary parameters returned to control values on PND 12. There was no effect on MT. Results from this study show that prenatal exposure to CdCl2 can induce significant changes in the kidney biochemistry of rats in the early postnatal period.

Ochratoxin A was given orally at 60 microgram/kg body weight in neutral olive oil to Fischer rats for 30 days, at which time they were killed. Clinical state, weights of animals and of their organs and urea and creatinine concentrations were not affected during the exposure period. Significant increases in the activity of enzymes in urine were found: 60% increase in alanine aminopeptidase, 45% increase in gamma-glutamyl-transferase and 90% increase in alkaline phosphatase. These changes indicate early pathological changes in the kidney. Relatively small amounts of the toxin thus affect kidney membrane cells.

The enzymatic profile of urine and plasma in field cases of bovine bladder cancer was studied. Urinary lactate dehydrogenase activity was significantly altered along with the isoenzyme pattern. Activity of alkaline phosphatase and beta-glucuronidase was decreased in the affected animals. No significant changes were observed in acid phosphatase, or arylsulphatase A and B activity. In plasma, lactate dehydrogenase activity was elevated without any change in the isoenzyme pattern. No significant changes were observed in the other plasma enzymes studied or in the sialic acid concentration.

The purpose of this study was to investigate the disposition and the nephrotoxicity of 3-amino-1-hydroxypropylidene-1, 1-bisphosphonate (APD-pamidronate) in order to elucidate the mechanism of the non-linearity of the renal elimination of this drug. The fate of APD labelled with [14C]APD was studied in mice and rats for a range of doses (0.5-40 mg/kg) and indicators of renal function were monitored. In both species, the percentage of dose excreted during the first 24-h after treatment fell dramatically as a function of the dose. However, the renal burden of APD rose linearly for doses of APD below 10 mg/kg and increased non-linearly over this threshold. In contrast the concentration of APD in both bone and liver, which together account for a large proportion of the dose, appeared to increase proportionally with dose. There was no evidence, therefore, that the non-linear renal elimination of APD was due to an increased uptake of APD by tissues. Conversely, the significant fall in the renal excretion of APD was paralleled by a striking loss in body weight, and for high doses, by a fall in the creatinine clearance. An increased enzymuria suggested the loss of brush border membranes and the release of lysosomal contents by proximal tubular cells. Morphological studies confirmed this and revealed a focal proximal tubular necrosis 6 days post dosing. We conclude that the nephrotoxicity of APD accounts for the non-linear renal elimination of this drug.

The involvement of metallothionein (MT) in the nephrotoxicity of cis-diamminedichloroplatinum (c-DDP) was investigated in rats using enzyme excretion and histology as indicators of renal damage. In addition, the effects of renal glutathione (GSH) depletion on the nephrotoxicity of c-DDP was assessed by organic anion transport in renal cortical slices. A dose of 6.0 mg c-DDP/kg body wt, i.p. was administered to rats either as a single injection of 6.0 mg/kg or as six daily injections of 1.0 mg/kg. Concentrations of platinum (Pt) after c-DDP injection in both dosing regimens were approximately 12 micrograms/g in kidney and 2 micrograms/g in liver. However, there were no increases in either hepatic or renal concentrations of MT after both series of c-DDP injections. Fractionation of kidney cytosols from c-DDP injected rats on Sephadex G-75 columns revealed that 60-70% of cytosolic Pt was associated with proteins of high molecular weight and 15-20% of the Pt associated with the low molecular weight ligands. No discernable Pt peak was detected in the elution volume of MT. Pretreatment of rats with ZnSO4 increased both hepatic and renal concentrations of MT, but there was no Pt associated with the MT fraction after a subsequent injection of c-DDP. Small increases in the urinary excretion of the lysosomal enzyme, N-acetyl-beta-D-glucosaminidase and two brush border enzymes, alkaline phosphatase and gamma-glutamyltranspeptidase were observed 2 and 3 days after a single injection of c-DDP (6.0 mg/kg body wt, i.p.). Urinary creatinine excretion decreased by 50% 1 day after c-DDP injection and continued to decrease for the next 2 days. On the third day after c-DDP treatment, a small but significant decrease in body weight was also observed in the c-DDP injected animals. Pretreatment with Zn did not alter the c-DDP-induced enzymuria or renal tubular damage but slightly attenuated both the decrease in creatinine excretion and the loss in body weight. Uptake of the organic anion, p-aminohippuric acid (PAH) was reduced at 12 and 24 h after c-DDP injection. Reduction of tissue GSH concentrations by pretreatment with buthionine sulfoxime (BSO), resulted in only a slight increase in the c-DDP-induced inhibition of PAH uptake at 24 h after c-DDP injection. These results suggest that, in rats, neither MT nor GSH appear to play major roles in the binding or nephrotoxicity of c-DDP.

Hexachlorobenzene (HCB) exposure has been shown to induce hyperparathyroidism and osteosclerosis in rats. Experiments were undertaken to investigate the effects of HCB-induced hyperparathyroidism and osteosclerosis on femur morphometry as well as femur breaking strength. Fischer 344 rats were dosed 5 d/wk for 15 wk with 0, 0.1, 1, 10, or 25 mg HCB/kg body weight. Hyperparathyroidism was produced in the two higher dose groups as reported previously (Andrews et al., 1989). Femur weight was significantly increased in the rats receiving 0.1, 1, and 25 mg HCB/kg body weight, whereas density was increased significantly at 1, 10, and 25 mg HCB/kg dose levels. Bone strength was also significantly increased at the three higher dose levels. Cross-sectional area of the midpoint of the femur was significantly increased at the 1 mg/kg HCB dose level. Cortical area and the proportion of the total area of the bone that the cortex occupied were significantly increased at the three higher dose levels. Medullary cavity area was significantly increased at the 0.1 mg/kg dose level but significantly decreased at the 2 higher dose levels of HCB. The right femur was significantly predominant to the left femur in weight, volume, and density through all dosing regimens. HCB exposure significantly altered bone morphometry and strength characteristics in the Fischer 344 rat.

Eight children with terminal renal insufficiency on continuous ambulatory peritoneal dialysis were followed for 12 months to evaluate laboratory parameters of mineral ion and bone metabolism. Calcium carbonate (range 47-295 mg/kg body weight per day) was given in combination with low doses of either vitamin D or 1,25(OH2D3. Blood urea nitrogen and serum phosphate concentrations remained well controlled throughout the observation period. A significant increase in serum calcium levels from 2.35 +/- 0.18 to 2.61 +/- 0.22 mmol/l (mean +/- SD) was observed during the first 6 months. Alkaline phosphatase activity and mid-C-regional parathyroid hormone, both indirect parameters of bone metabolism, revealed no evidence of severe secondary hyperparathyroidism. Our data indicate that calcium carbonate may be sufficient to induce relative hypercalcaemia in uraemic children, and thus reduce the risk of developing renal osteodystrophy. Unwanted side-effects of vitamin D preparations, i.e. increased intestinal phosphate absorption and hypercalcaemia after successful renal transplantation, may thus be avoided.

We detected in urine by HPLC two enzyme fractions of alkaline phosphatase (AP, EC 3.1.3.1), soluble and particulate, analogous to those in serum. The second fraction was eluted with high-salt-content eluent at the same elution time as high-molecular-mass, or particulate, AP in serum. AP characterization in urine from a patient with acute rejection crisis showed a greater sensitivity of the particulate form to treatment with L-phenylalanine, which suggests a higher content of intestinal-type AP in the particulate form. The soluble fraction showed a more liver-type AP behavior. Changes in the chromatograms after the sample was treated with 1-butanol and Triton X-100 support a membrane origin of the particulate AP. Urinalyses from patients with acute renal disease showed increased activity of soluble and particulate AP, with a relatively greater increase of particulate AP.

This study was designed to evaluate the effects of endotoxin infusion (0.25 mg/kg) over a 4-hr period on renal function and tubular enzyme activity. Endotoxin administration resulted in a decrease in blood pressure, osmolar clearance, and creatinine clearance (P less than 0.05). The enzyme activities of alkaline phosphatase (ALP) and lactic dehydrogenase (LDH) in the urine increased, as did the serum creatinine (P less than 0.05). There were no significant changes in the renal artery flow, urinary output, heart rate, serum electrolytes, and serum enzyme activities. In contrast, in the saline control group, the renal artery flow increased (P less than 0.05), whereas the serum creatinine, urinary ALP, and urinary LDH decreased over time. All other parameters remained relatively stable. These data suggest that an increase in urinary enzyme activity reflects compromised renal function and is independent of the renal artery flow. This may have clinical application in detecting early renal damage due to endotoxemia or sepsis.

The aim of this study was to clarify the clinical significance of urinary enzyme activity in patients with diabetes mellitus. Patients were divided into two groups: group A - 102 outpatients, group B-23 inpatients. Spot urine samples before breakfast from group A and aliquots of 24-hours urine collections at 4 degrees C from group B were used. Urinary enzyme activities (N-acetyl- beta-D-glucosaminidase: NAG, alkaline phosphatase: ALP, leucine aminopeptidase: LAP, gamma-glutamyl transpeptidase: gamma-GTP) were determined by spectrophotometric assay, rate assay, Tuppy method and Orlowski method, respectively. 1) In group A, the percentage of the cases which showed higher than the normal range (NAG: 1.3-8.7, ALP: 4.2-17.7, LAP: 0-22.9 U/g. cer.) was 42.2% in NAG, 21.6% in ALP, and 8.8% in LAP. In a multiple regression analysis, the predictor variables which contributed to NAG were HbA1c, age, urinary protein and the one that contributed to ALP, LAP, gamma-GTP was urinary beta 2-microglobulin. 2) In group B, 87% of NAG was above the normal range (Mean +/- 2 SD; 4.8 +/- 3.9 U/day). There was no difference in the NAG activity between patients with and without nephropathy. The percent of high activities of ALP, LAP and gamma-GTP were 17%, 17%, 4%, respectively. Most of them were patients with nephropathy. There were correlations among ALP, LAP and gamma-GTP, though no correlation existed between NAG and the other three enzymes. These results suggested: 1) NAG reflects lysosomal dysfunction of both glomerular and proximal tubular epithelial cells which may be caused by poor glycemic control.(ABSTRACT TRUNCATED AT 250 WORDS)

Renal toxicity was assessed in 19 patients receiving methyl acetylenic putrescine (MAP), an irreversible inhibitor of ornithine decarboxylase. Patients received 250 mg t.d.s. for up to 13 weeks. This dose effectively inhibited the target enzyme, as shown by elevations in decarboxylated S-adenosyl methionine levels. No significant nephrotoxicity was observed in these patients as determined by plasma urea, creatinine and creatinine clearance measurements, although minor elevations of the urinary enzymes lactate dehydrogenase, N-acetyl-beta-glucosaminidase, alkaline phosphatase and alanine aminopeptidase were observed. As this could represent sub-clinical renal damage, caution should be exercised when using MAP in combination with other cytotoxic drugs.

The hyperexcretion of urinary enzymes with systemic Lupus Erythematosus (SLE) was assayed. 31 patients with confirmed SLE (30 women, and 1 man, age 16-33 years) were studied. Patients were divided into two groups according to the degree of kidney damage: 21 patients with proteinuria, and 10 patients without proteinuria. 12 patients of the first group had nephrotic syndrome (NS). 30 practically healthy subjects served as a control group. In patients with Lupus-nephritis (LN) the increase of activities of urinary GGT, AP, BGRS, NAG, and CHE was observed, the increase was especially clearly shown in LN-patients with NS. The increase of activity of urinary GGT and NAG was shown in the group of SLE patients who did not have clinical and laboratory signs of LN, which can be used as early index for the damage of tubular epithelium.

Urinary excretion of alanine aminopeptidase, alkaline phosphatase, gamma-glutamyltransferase and N-acetyl-beta-D-glucosaminidase was determined in gel-filtered samples of morning random urine specimens of 442 subjects of various ages (5 days to 58 years). Enzyme excretion related to urinary creatinine (enzyme/creatinine ratio; U/mmol creatinine) significantly decreased with increasing age. Sex-related differences of some enzyme excretions were found in age groups over 6 years. From these investigations, we calculated upper reference intervals (97.5 percentiles) for 5 age-dependent groups of children and adolescents and for one group of adults.

Renal function was assessed in 20 (11 female and 9 male, age 21-76 years, mean 53) renal patients with a creatinine clearance 25-145 ml/min, mean 95, to evaluate the effects of iohexol, a non-ionic low-osmolar contrast medium. Intravenous urography was performed in 16 patients and computed body tomography in 4, using a dose of iohexol ranged between 0.6-3.3 (mean 1.17) g/kg b.w. Different parameters of renal function were determined in the week preceding and 1, 3 and 5 days after the administration of iohexol. The principal renal effect of iohexol was an increase of urinary alanine aminopeptidase, gamma-glutamyltransferase, lactate dehydrogenase, alkaline phosphatase and N-acetyl-beta-D-glucosaminidase. The maximum increase of enzymuria was observed on day 1 after the administration of iohexol. In most cases enzymes returned to base-line values within 3 days. No relevant variation of renal hemodynamics (glomerular filtration rate and effective renal plasma flow) was observed after iohexol. In conclusion, iohexol can increase of urinary enzymes, but the effect is rapidly reversible and is not accompanied by a clinically significant impairment of renal hemodynamics.

Excretion of urinary N-acetyl-beta-glucosaminidase (NAG), lactate dehydrogenase (LDH), alkaline phosphatase (ALP) and gamma-glutamyltransferase (gamma-GT) was studied following single intravenous administrations of a non-ionic monomeric contrast medium (iohexol) at doses of 5.0, 7.5, 10.0 and 12.5 g iodine/kg body wt in rats. Measurements of urinary enzymes, serum urea nitrogen and serum creatinine were carried out on the 2nd, 3rd, 4th and 8th days after treatment. Histological examinations of kidneys were performed on days 3 and 8. From 5.0 g iodine/kg onwards urinary NAG showed a dose-dependent and significant (multiple comparison, alpha = 0.05) increase in the first 18-h urine samples after application. A significant increase in urinary LDH could be observed only at the highest dose of 12.5 g iodine/kg. All other biochemical parameters showed no differences when compared to the control group. The dose-dependent increase in lysosomal NAG correlated with the histological findings, i.e. there was dose-dependent vacuolization of proximal tubular cells, so-called 'osmotic nephrosis'.

Fourteen guinea pigs were injected with sublimate during the period of 3 months. Their urine and blood was examined. In the urine an increase of activity of alkaline phosphatase and lactate dehydrogenase was noted. In the blood plasma an increase of lactate dehydrogenase activity was observed and in the blood serum decrease of gamma-glutamyl-transpeptidase activity. The determination of alkaline phosphatase in urine is a sensitive indicator of renal damage caused by mercury. It has a greater diagnostic value than the determination of this enzyme in the blood serum.

The renal toxicity of the ionic, very hyperosmolaric megluminamidotrizoate was compared with the toxicity of the non-ionic, slightly hypertonic iopamidol after intravenous injection of 0.7 ml/kg body weight (i.e. about 300 mg iodine/ml) in a randomized study of 20 individuals with normal kidneys. Quantitative measurements of the excretion of the enzymes, lactate dehydrogenase (LDH), alkaline phosphatase (AP), and N-acetylglucosaminidase (NAG) in 24-h urine samples, serum creatinine, and the endogeneous creatine clearance were conducted to determine the possible renal damage. All 20 subjects tolerated both contrast mediums well. Reduced renal function as measured by the creatinine blood level and the endogeneous clearance did not occur. The ionic, hyperosmolaric megluminamidotrizoate++ caused significantly elevated enzymuria of NAG, AP, and LDH (P less than 0.01) following tubular irrigation, whereas iopamidol showed no significant enzymuria. Therefore, it appears that the non-ionic contrast medium, iopamidol, is less toxic for kidneys than the ionic megluminamidotrizoate.

A damage of the kidney, particularly of proximal tubular cells, can be indicated by an increased concentration of definite enzymes in urine. After gynecological operation the repeated application of 8 g cephalothin daily provokes an higher increase of enzyme concentrations in urine than the application of ampicillin under the same conditions. These results show that cephalothin produces a slight alteration of tubular cells, probably without practical importance. In contrast to this, in children a total dose of 1.5 up to 6 g cephalothin, administered after an operative correction of vesikoureterale reflux, provokes no marked changes in urinary enzyme excretion. Probably, in these children the determination of urinary enzyme excretion is not a suitable parameter to demonstrate a slight tubulotoxic damage.

Biochemical changes in rat urine and tissues treated with five consecutive daily doses of ochratoxin A (10 mg/kg body weight) were studied. Urine volume and urinary proteins were moderately raised during the first few days of ochratoxin treatment, and were then highly elevated towards the end of the investigation. Urinary muramidase excretion was significantly raised (p less than 0.01) 24 h after the first insult with the toxin. The urinary output of alkaline and acid phosphatases, lactate dehydrogenase (LDH) and glutamate dehydrogenase (GDH) were all elevated but very much later, during the course of injections with ochratoxin A. Kidney alkaline and acid phosphatases, LDH and GDH were correspondingly reduced 7 days from the beginning of ochratoxin A administration. Liver LDH activity was reduced while serum LDH was raised. Liver glycogen level was significantly (p less than 0.0001) increased. Experimental evidence was presented to show that the initial point of interaction of ochratoxin A with the rat renal system may be at the first portion of the proximal convoluted tubular cell region.

The effect of prostaglandin E1 alpha-cyclodextrin host molecule (PGE1 . CD) was estimated by using a model of immune complex glomerulonephritis induced in rats by i.v. injection of 1 mg of rabbit serum albumin every other day. PGE1 . CD was given subcutaneously for 10 days after nephritis was definitely induced and resulted in a rapid restoration of various biochemical parameters, especially in plasma. The continuous s.c. administration of PGE1 . CD (300 micrograms/rat/day) with a mini osmotic pump provoked a therapeutic effect similar to that obtained with twice daily s.c. administration of PGE1 . CD (300 micrograms/rat X 2/day). Both PGE1 . CD groups revealed less glomerular damage and fewer locations of immune complexes in glomeruli as demonstrated by light and immunofluorescence microscopy. The beneficial effect of PGE1 . CD may be associated with reduced immune complex deposits in glomeruli. The present studies suggest that PGE1 . CD may enhance the clearance of immune complex deposits from the glomeruli rather than inhibiting the formation of immune complex in the circulation.

Urinary alkaline phosphatase has been measured and an investigation has been undertaken involving starch gel electrophoresis after treatment of the enzyme with antisera raised against various human tissues. Urine was obtained from patients with bone and liver disease as well as pregnant women and normal persons. The enzyme level in urine in disease and pregnancy was raised above the normal but considerable overlap occurred. After electrophoresis the most usual finding was a single zone of activity although occasionally very minor zones were also present. Antiserum to kidney had the greatest affinity for the urinary enzyme. Decreasing affinity was found with intestinal and placental antiserum. No affinity was found with liver antiserum.

The elevation of urinary trehalase activity in patients of itai-itai disease was examined. Urinary trehalase was correlated with tubular reabsorption of phosphorus (%TRP): the lower the trehalase activity, the worse was %TRP. Furthermore, this activity was inversely correlated with urinary glucose and urinary total protein. In itai-itai disease, the excretion of beta 2-microglobulin seems to be maximal, and urinary trehalase activity was low in the latter stages of the disease. It is inferred that itai-itai disease produces extremely severe tubular damage as well as glomerular dysfunction.

We determined the urinary excretion of the enzymes aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-glucosaminidase (EC 3.2.1.30) in two groups of renal-transplant recipients at different times after transplantation (1.8 months and 52 months, respectively). Both groups of patients showed a higher rate of enzyme excretion than did a reference group of healthy persons. More aminopeptidase and N-acetyl-beta-glucosaminidase were excreted during the early period after transplantation than later. The time-dependence of urinary enzyme excretion was confirmed in six renal-transplant recipients studied during the course of 15 months after transplantation. There was a general correlation between the extent of urinary enzyme excretion and both the time after transplantation and the daily dose of prednisolone. Therefore, it is necessary to take into account this influence on the extent of urinary enzyme in renal-transplant recipients if urinary enzyme excretion is used as an indicator of renal disorder and especially as an early predictor of transplant rejection.

Male Wistar rats were dosed daily by gavage for 200 days with either (1) aspirin, 200 mg/kg; (2) acetaminophen, 200 mg/kg; (3) aspirin and acetaminophen, 200 mg/kg of each; (4) aspirin and acetaminophen, 100 mg/kg of each or (5) vehicle alone. None of the treatments produced any marked signs of toxicity and no drug related deaths were observed. The full dose combination (3) did significantly reduce the weight compared to the control group (5). When urinary lactic dehydrogenase and alkaline phosphatase were measured, all treatments caused some increase in activity but those containing aspirin had the greatest effect. Urinary pH and osmolarity were not effected by the treatments. Complete pathological examination of the animals failed to detect any significant changes when compared to the controls. It is concluded that there is no evidence of a toxic interaction between aspirin and acetaminophen in the rat.

8 patients with chronic pyelonephritis were given gentamycin intramuscularly injected in individual dosage during 8-10 days. Here the behaviour of the excretion of protein, alanine aminopeptidase alkaline phosphatase, alpha-glucosidase, gamma-glutamyl transpeptidase and lysozyme with the urine was tested. With the exception of the lysozymuria, which increased only in patients with chronic renal insufficiency, regularly a hyperenzymuria developed. Most distinctly the excretion of the alanine aminopeptidase increased. After initial decrease the excretion of total protein transiently increased after completion of the gentamycin therapy. All the deviations were reversible. From the increased excretion of enzymes may not be concluded to a nephrotoxicity of gentamycin.

The urinary brush-border enzymes alanine aminopeptidase, alkaline phosphatase and gamma-glutamyltransferase can be separated by ultracentrifugation into a particulate and a soluble fraction. These variants have been characterized with respect to their kinetic data, heat stability, electrophoretic mobility and behaviour in gel chromatography and affinity chromatography. Both variants of these enzymes show nearly identical Km values and activity curves as functions of rho H and substrate concentration. The particulate variant is more heat-sensitive than the soluble one. The soluble variant as well as the particulate form consist of one fraction bound by Con A-sepharose and another one unbound by it. Origins and nature of these multiple variants in connection with their possible diagnostic significance are discussed.