Renal tolerance of cefpirome (HR 810), a new cephalosporin antibiotic

An open study was carried out in ten healthy, male volunteers in order to investigate the renal tolerance of cefpirome (HR 810), a new cephalosporin antibiotic. Subjects received a single dose of 1.0 g of cefpirome and then repeated doses of 1.0 g of cefpirome twice daily for five days. Urine was collected in several fractions during the study and the urine excretion, excretions of creatinine, N-acetyl-beta-D-glucosaminidase, gamma glutamyltransferase, alanine aminopeptidase and lactate dehydrogenase were calculated in 12-hour fractions. Serum creatinine (using an enzymatic method), beta 2-microglobulin concentrations and creatinine clearance were also determined. Based on the findings of these renal enzymes, renal tolerance was good. This was also confirmed by creatinine clearance calculations and follow-up of serum beta 2-microglobulin levels. Cefpirome showed good renal tolerance without any signs of nephrotoxicity in this study with the methods used.

Age related changes of N-acetyl-beta-D-glucosaminidase and L-alanine aminopeptidase in mouse kidney, urine and plasma

Age and sex dependent differences of N-acetyl-beta-D-glucosaminidase (NAG) and L-alanine aminopeptidase (AAP) activities in kidney, urine and plasma of male and female mice were studied. The sex difference in NAG activity appeared between 27 and 38 days of age with the manifestation of significant differences in body weight and kidney growth. NAG activity in male kidneys was 3-fold that in females and its urinary level in mature males was over 10-fold higher. Androgenic regulation was found not only in the NAG contents in the kidneys and in the urinary excretion but also in the plasma NAG level, which showed higher in females. On the other hand, AAP activity in kidney, urine and plasma did not show much sex differences. Age related changes in AAP activity were not found except in the kidney and marked androgenic regulation was also not found in AAP. These results indicate that NAG and AAP, which are both urinary enzymes used as indicators of renal lesions, may be regulated differently.

Comparison of N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase activities for evaluation of microangiopathy in diabetes mellitus

The activities of urinary N-acetyl-beta-D-glucosaminidase (NAG) and alanine aminopeptidase (AAP) were measured in 207 diabetic patients and 57 healthy controls, and the relationship of these enzymes to different stages of diabetic microangiopathy was studied. Diabetics with clinical proteinuria had higher urinary NAG and AAP (17.7 +/- 1.9 and 42.8 +/- 4.9 U/g creatinine, mean +/- SE, respectively) than healthy controls (1.8 +/- 0.1 and 10.0 +/- 0.4) or diabetics without proteinuria. Among diabetics without proteinuria, NAG excretion in those with retinopathy was slightly higher than in those without (6.4 +/- 0.5 v 5.4 +/- 0.4), and AAP in those with retinopathy was significantly higher than in those without (23.0 +/- 1.5 v 17.4 +/- 0.8, P less than 0.01). Urinary albumin measured by radioimmunoassay and lysozyme in diabetics with retinopathy but without proteinuria was higher than those without retinopathy (P less than 0.001 and P less than 0.01). The increase in albumin was the greatest in diabetics with long duration of the disease (greater than or equal to 8 years); however, NAG and AAP increased more significantly in those with high hemoglobin A1c than in patients with long duration.(ABSTRACT TRUNCATED AT 250 WORDS)

Carboplatin (CBDCA), iproplatin (CHIP), and high dose cisplatin in hypertonic saline evaluated for tubular nephrotoxicity

We compared the acute tubular nephrotoxicity of three platinum compounds in children and adults with solid tumors by monitoring the urinary excretion of alanine aminopeptidase, N-acetyl-beta-D-glucosaminidase, and total protein. Cisplatin (100 mg/m2) was administered with mannitol, or at a twofold larger total dosage (50 mg/m2 per day for 4 days) in a 3% saline infusion. Carboplatin (300 mg/m2) was administered in combination with 5-fluorouracil, and iproplatin was administered in dosages ranging from 216 to 388 mg/m2. Enzymuria and proteinuria induced by cisplatin at a total dosage of 200 mg/m2 on a divided schedule did not significantly differ from that observed for the single 100 mg/m2 dose. Enzymuria and proteinuria induced by carboplatin and iproplatin were significantly less than that for cisplatin; however, one patient developed chronic tubular damage after three courses of carboplatin, and the acute tubular toxicity of iproplatin in one of 15 patients was exceptional. Our findings support the value of administering cisplatin in hypertonic saline on a divided schedule as a strategy to reduce acute tubular damage. Although carboplatin and iproplatin are less nephrotoxic than cisplatin, occasionally patients experience subclinical acute or chronic tubular damage that may lead to overt nephrotoxicity with continued therapy.

Ifosfamide-induced subclinical tubular nephrotoxicity despite mesna

We monitored acute tubular damage in 16 patients who received a 5-day course of ifosfamide (1.6 g/m2/day) and mesna (1.2 g/m2/day) therapy. Urinary concentrations of alanine aminopeptidase, N-acetyl-beta-D-glucosaminidase, and total protein increased in every patient, but the extent of tubular toxicity varied widely among patients. Evidence of toxicity was greatest in patients whose tumors involved the kidneys. The time course of enzymuria and proteinuria indicated tubular cell necrosis. We observed this acute toxic effect despite the administration of sufficient mesna to prevent hemorrhagic cystitis. Urinary marker concentrations returned towards pre-dose levels, and there were no increases in serum creatinine concentrations measured 3 weeks after treatment.

Tubular nephrotoxicity after intravenous urography with ionic high-osmolal and nonionic low-osmolal contrast media in patients with chronic renal insufficiency

Nephrotoxicity of intravenous contrast media is more frequent and striking in patients with risk factors, the major one being preexisting chronic renal insufficiency. New nonionic low-osmolal contrast media allegedly have less nephrotoxicity than the traditional ionic high-osmolal ones. This was tested for two contrast media in a group of 18 patients with stable chronic renal insufficiency. The urinary excretion of two brush-border enzymes (alanine aminopeptidase, AAP, and gamma-glutamyl transpeptidase, gamma-GT) and of a lysosomal enzyme (N-acetyl-beta glucosaminidase, NAG), functional markers of tubular injury, were measured before and after intravenous urography with an ionic high-osmolal radiocontrast medium, meglumine sodium diatrizoate, or with a non ionic low-osmolal one, iopamidol. Urinary NAG excretion did not change significantly after administration of either contrast media. Urinary AAP and gamma-GT excretion increased significantly (p less than 0.01) after diatrizoate. After iopamidol, only gamma-GT excretion increased significantly (p less than 0.05). Our data suggest that the nonionic low-osmolal radiocontrast medium iopamidol is less toxic to tubules than the ionic high-osmolal medium diatrizoate and that the brush-border enzymes AAP and gamma-GT are sensitive markers for this toxicity.

Enhancement of methotrexate nephrotoxicity after cisplatin therapy

We measured urinary levels of total protein, N-acetyl-beta-D-glucosaminidase (NAG), alanine aminopeptidase, and adenosine deaminase-binding protein in ten children with osteogenic sarcoma who were receiving combination chemotherapy that included 12 doses of methotrexate (12 g/m2). Analysis of the changes in these sensitive markers of renal tubular damage permitted detection of subclinical methotrexate-induced nephrotoxicity. In the absence of cisplatin, methotrexate therapy was associated with significant but transient increases in each of the four markers. Irreversible nephrotoxicity, indicated by persistent rises in NAG and alanine aminopeptidase as well as increased serum creatinine levels, was associated with doses of methotrexate that followed the administration of cisplatin (400 mg/m2). The biphasic pattern of total protein and NAG excretion observed in all patients suggests more than one mechanism of methotrexate-induced nephrotoxicity. Monitoring renal tubular damage in patients who are receiving methotrexate in combined-drug regimens would provide useful information for scheduling nephrotoxic drugs in clinical trials.

[Determination of enzyme activities in urine of patients with calcium oxalate calculi]

The catalytic activity of lactate dehydrogenase, gamma-glutamyltransferase, alkaline phosphatase, alanine aminopeptidase and N-acetyl-beta-D-glucosaminidase has been measured in 24 h urines of patients with a calcium oxalate calculus (9 men, 11 women) and has been compared with those of a reference collective (11 men, 10 women). The diagnostic sensitivity and the diagnostic specificity have been calculated according to four different discrimination methods in which the diagnostic sensitivity lies between 65% and 100%, the diagnostic specificity between 72% and 100%. Within the reference group there was a correlation between the excretion of the three brush-border enzymes, whereas within the group of patients only a correlation between gamma-glutamyltransferase and N-acetyl-beta-D-glucosaminidase was observed. From this pathophysiological conclusions can be drawn.

Renal function in cystic fibrosis: proteinuria and enzymuria before and after tobramycin therapy

Proteinuria and enzymuria were measured in 27 patients with Cystic Fibrosis before and after tobramycin therapy. Prior to treatment, kidney function was normal in 23 patients. Four patients showed a pathological proteinuria and two haematuria. Renal biopsy in one patient showed segmental basement membrane alterations on electron microscopy; there were no immunoglobulin deposits. During intravenous therapy with tobramycin (10 mg/kg per day) and azlocillin (100 mg/kg per day) mean urinary N-acetyl-beta-D-glucosaminidase (NAG) excretion rose six-fold and mean urinary alaninaminopeptidase excretion increased ten-fold. After cessation of therapy, enzymuria rapidly returned to pretreatment values in all 14 patients. Aerosol tobramycin therapy in four patients did not affect urinary excretion of NAG. It can be concluded that tobramycin did not cause persistent renal damage in our patients, whether given intravenously or as an aerosol.

[Enzymuria and kidney diseases in childhood]

Urinary enzyme excretion and proteinuria were studied in 316 children with different underlying diseases. Activities on N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase decreased progressively with age in the urine of 66 healthy prematures, newborns, infants or children. In 51 children with nephrotic syndrome, tubulopathies or chronic renal failure, excretion of NAG and AAP rose 3 to 30 fold. Contrary to molecular weight dependent protein analysis, determination of enzymuria did not allow to differentiate between glomerular and tubular disorders. After renal transplantation, 31 out of 52 children had a pathological enzymuria. NAG and AAP were more frequently elevated during treatment with cyclosporine A (21/29), than with azathioprine (10/23). The influence of nephrotoxic drugs upon enzymuria was documented in 14 children with cystic fibrosis or septicaemia treated with tobramycin. Activities of NAG and AAP rose transiently, whereas proteinuria remained almost unchanged. Only three out of 45 children receiving nonsteroidal antiinflammatory drug therapy for juvenile rheumatoid arthritis or spondylarthritis showed a pathological increase in enzymuria. Mean urinary NAG and AAP excretion in 154 children with insulin dependent diabetes mellitus were not different from controls and were unrelated to either duration of disease or HbA1 concentration. The determinations of urinary enzymes as non-invasive tests of renal integrity in medicine and toxicology provide a very sensitive indicator of renal damage. The assays of NAG and AAP have proven to be most valuable; however, due to a lack of specificity for the type and origin of renal dysfunction, these urinary enzyme assays are most useful when carried out in conjunction with electrophoretic analyses of proteinuria.

Identification of inhibitors of urinary alanine aminopeptidase

Amino acids and ammonia were identified as natural inhibitors of urinary AAP. In urines from healthy volunteers approximately one half of the inhibition could be accounted for by amino acids and ammonia. At the measured concentrations, histidine, ammonia and phenylalanine, in decreasing order, were the most effective inhibitors. Results from kinetic studies with amino acids added to gel-filtered urine are consistent with the presence of two AAP isoenzymes with different inhibition characteristics. The ten amino acids which were tested show the same inhibition kinetics. Differences between amino acids are quantitative.

Value of enzyme determinations in urine for the diagnosis of nephrotoxicity in rats

Excretion of urinary lactate dehydrogenase (LDH, EC 1.1.1.27), gamma-glutamyltransferase (gamma-GT, EC 2.3.2.2), alkaline phosphatase (ALP, EC 3.1.3.1), alanine aminopeptidase (AAP, EC 3.4.11.-), alanine aminotransferase (GPT, EC 2.6.1.2) and N-acetyl-beta-D-glucosaminidase (NAG, EC 3.2.1.30) was studied following a single i.v. application of 1 mg mercuric chloride/kg body weight or a radio contrast medium (SH H 340 AB) at a dose of 7.5 g iodine/kg body weight in rats. Measurements of urinary enzymes and serum urea nitrogen and creatinine were carried out on the second, third, fourth and ninth days after treatment. Histological examinations of kidneys were performed on day 9. A drastic increase in urinary LDH and moderate increase in gamma-GT, ALP and AAP and a very slight increase in GPT was observed in the first 18-h urine samples after mercuric chloride. This increase in enzymuria was associated with a drastic increase in serum urea nitrogen and creatinine, with a maximum on day 4. The radio contrast medium-treated animals showed a similar but less pronounced pattern of urinary enzymes excretion and only a slight increase of serum urea nitrogen on day 2. A good correlation was found between histological findings and enzymuria as well as serum urea nitrogen and creatinine. Thus, determination of only some urinary enzymes (LDH and gamma-GT) is valuable in predicting early nephrotoxicity and sufficient for the diagnosis of proximal tubule damage in rats.

Increased levels of urinary adenosine deaminase binding protein in children treated with cisplatin or methotrexate

Levels of adenosine deaminase binding protein (ABP), a renal tubular cell antigen, were determined by enzyme immunoassay in urine specimens from seven children with solid tumors who were receiving the recognized nephrotoxins cisplatin or methotrexate. ABP excretion was uniformly increased within the first 3 days after administration of either drug. Elevated ABP levels were usually accompanied by increased excretion of the urinary enzymes N-acetyl-beta-D-glucosaminidase and alanine aminopeptidase. In alkaline urine specimens associated with methotrexate therapy, ABP levels were increased whereas enzyme activities appeared to be unstable. Hence, immunochemical measurement of urinary ABP levels may be adjunctively useful for clinical studies of renal tubular damage.

Diagnostic significance of some urinary enzymes for detecting acute rejection crises in renal-transplant recipients: alanine aminopeptidase, alkaline phosphatase, gamma-glutamyltransferase, N-acetyl-beta-D-glucosaminidase, and lysozyme

We compared the diagnostic validity of five urinary enzymes--alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), and lysozyme (EC 3.2.1.17)--as indicators of acute rejection crises in renal-transplant recipients. In 82 patients (group A), the excretion of each of these five enzymes was measured daily from transplantation until discharge from hospital. In another 69 patients (group B), enzyme determinations were made when the patient came for regular checkups (about every four to eight weeks). We used an "activity ratio" (the activity measured at a particular time compared with the activity on the preceding determination) value of 1.5 as the decision point. In group A, use of this discrimination point for alanine aminopeptidase, gamma-glutamyltransferase, and N-acetyl-beta-D-glucosaminidase yielded a specificity and sensitivity of about 90%. In group B, only alanine aminopeptidase had a greater diagnostic sensitivity than creatinine alone. Evidently, measurement of alanine aminopeptidase can be a helpful indicator of acute rejection crises, when interpreted in combination with other available relevant clinical, biochemical, and immunological data.

[Renal dipeptidylpeptidase IV excretion in drug-induced kidney changes]

The course of the excretion of dipeptidyl-peptidase IV (DP IV)-alanine aminopeptidase, beta-glucuronidase and total protein with the urine was investigated during the treatment of 11 patients with pyelonephritis with gentamicin, after application of a renal radiographic contrast medium in 7 patients with arterial hypertension and after regional perfusion of an extremity in 10 patients with malignant melanoma. In the reference group in male test persons with 147.0 nmol/s X l a higher DP IV activity in the urine was recognized than in the female test persons (100.0 nmol/s X l). After application of the drugs a rhythmically intermitting increased excretion of all enzymes mentioned develops. The study confirms the usuability of the DP IV-activity for enzymological investigations of the urine.

Cumulative renal tubular damage associated with cisplatin nephrotoxicity

We assessed the acute and chronic effect of multiple courses of cisplatin therapy on renal tubules by monitoring the urinary excretion of alanine aminopeptidase, N-acetyl-beta-D-glucosaminidase, and total protein. Urine specimens were obtained before and after doses of cisplatin (90 mg/m2) given to 12 patients. Each dose of cisplatin induced transient increases in enzyme excretion, followed by proteinuria 3-5 days later. Transient enzymuria after the last cisplatin dose was significantly greater than that after the first dose. Moreover, persistent increases in urinary N-acetyl-beta-D-glucosaminidase and serum creatinine concentrations over pretherapy levels indicated chronic renal tubular damage. Our findings disclosed striking differences between patients in susceptibility to progressive nephrotoxicity.

Diuresis-dependent excretion of multiple forms of renal brush-border enzymes in urine

The urinary brush-border enzymes alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1) and gamma-glutamyltransferase (EC 2.3.2.2) and their activity pattern of soluble and particulate forms separated by ultracentrifugation were investigated over 8 h after a high intake of fluid (22 ml/kg body wt.). The activity pattern of the two multiple forms was markedly influenced by the urine flow rate. The time-related excretion of soluble forms of these three enzymes increased with the extent of urine output whereas the excretion of particulate form was independent on diuresis. Diuresis-dependent excretion of total activities of brush-border enzymes can be exclusively considered to be a consequence of changed excretion of soluble forms.

[Behavior of certain forms of enzymuria in subjects treated with pipemidic acid]

Three groups of subjects (I with infections of the lower urinary ways; II with chronic pyelonephritis; III healthy controls) were treated with pipemidic acid for 10 consecutive days and the behaviour of their urinary NAG and AAP was studied. It was discovered that the healthy group and the patients with infections of the lower urinary ways showed no significant variations in the urinary activity of the two enzymes following the administration of pipemidic acid. However there was a distinct reduction in both enzymes in patients with chronic pyelonephritis who presented demonstrable bacterial sensitivity to the drug. Apart from the fact that it produces no nephrotoxic effects at least in the doses used and for the treatment period adopted, the drug is therefore considered to reduce renal inflammation that is beneficial to individuals with chronic interstitial nephropathy.

Different diuresis-dependent excretions of urinary enzymes: N-acetyl-beta-D-glucosaminidase, alanine aminopeptidase, alkaline phosphatase, and gamma-glutamyltransferase

We studied how much of the lysosomal enzyme N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30) and of the brush-border enzymes alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), and gamma-glutamyltransferase (EC 2.3.2.2) was excreted in urine over 8 h after a high intake of fluid (22 mL per kilogram of body weight). The hourly excretion of all four enzymes increased with the increasing urine flow rate. The excretion rate of the brush-border enzymes was more markedly influenced than that of N-acetyl-beta-D-glucosaminidase. By relating the enzyme excretion to urinary creatinine we could reduce the variability of brush-border enzyme output and could completely compensate for the effect of diuresis on the excretion of N-acetyl-beta-D-glucosaminidase.