Identification of novel translational urinary biomarkers for acetaminophen-induced acute liver injury using proteomic profiling in mice

Drug-induced liver injury (DILI) is the leading cause of acute liver failure. Currently, no adequate predictive biomarkers for DILI are available. This study describes a translational approach using proteomic profiling for the identification of urinary proteins related to acute liver injury induced by acetaminophen (APAP). Mice were given a single intraperitoneal dose of APAP (0–350 mg/kg bw) followed by 24 h urine collection. Doses of ≥275 mg/kg bw APAP resulted in hepatic centrilobular necrosis and significantly elevated plasma alanine aminotransferase (ALT) values (p<0.0001). Proteomic profiling resulted in the identification of 12 differentially excreted proteins in urine of mice with acute liver injury (p<0.001), including superoxide dismutase 1 (SOD1), carbonic anhydrase 3 (CA3) and calmodulin (CaM), as novel biomarkers for APAP-induced liver injury. Urinary levels of SOD1 and CA3 increased with rising plasma ALT levels, but urinary CaM was already present in mice treated with high dose of APAP without elevated plasma ALT levels. Importantly, we showed in human urine after APAP intoxication the presence of SOD1 and CA3, whereas both proteins were absent in control urine samples. Urinary concentrations of CaM were significantly increased and correlated well with plasma APAP concentrations (r = 0.97; p<0.0001) in human APAP intoxicants, who did not present with elevated plasma ALT levels. In conclusion, using this urinary proteomics approach we demonstrate CA3, SOD1 and, most importantly, CaM as potential human biomarkers for APAP-induced liver injury.

[Protection effect and mechanism of Compound Xueshuantong Capsule on diabetic nephropathy rats]

OBJECTIVE

To explore the renoprotective effect of Compound Xueshuantong Capsule (XST) on diabetic rat model with nephropathy.

METHODS

Twenty-eight male Sprague Dawley diabetic rats were induced to hyperglycaemia (3 days later, fasting blood glucose > 16.7 mmol/L) by peritoneal injection with streptozotocin (STZ, 50 mg/kg). And they were divided into four groups: diabetic nephropathy (vehicle treatment), irbesartan (20 mg×kg(-1)×d(-1)), low-dosage XST (900 mg×kg(-1)×d(-1)) and high-dosage XST (1800 mg×kg(-1)×d(-1)). Seven normal rats were used as control. After a 12-week intervention, urine protein was examined. Pathological morphology was observed by hematoxylin-eosin (HE), Masson and (periodic acid Schiff) PAS stains. Blood nitric oxide (NO), malondialdehyde (MDA) and blood superoxide dismutase (SOD) and urine SOD were detected. And the expression of (matrix metalloproteinase-2) MMP-2 was detected by Western blot in each group.

RESULTS

The model rats presented with hyperglycemia, polydipsia, hyperphagia, polyuria and hyper microalbuminuria. The intervention groups showed decreased microalbuminuria and there was no effect on blood glucose or body weight. Glomerular sclerosis and extracellular matrix (ECM) increased in model group and improved in irbesartan and XST groups as judged by HE, Masson and PAS stains. Three intervention groups had no effect on the elevated expression of MMP-2 in diabetic rats. Compared with the model group, the irbesartan, low-dosage and high-dosage XST groups had significantly decreased blood levels of NO ((104.9 ± 11.0) µmol/L vs (41.9 ± 9.6) µmol/L and (14.7 ± 1.9) µmol/L, P < 0.05) and MDA ((19.6 ± 1.6) nmol/L vs (6.6 ± 0.9) mol/L and (4.5 ± 1.2) nmol/L, P < 0.05), increased blood and urine activities of SOD (blood: (222 ± 20)×10(3) vs (231 ± 18)×10(3) and (237 ± 24)×10(3) U/L,P < 0.05), urine: (11.8 ± 1.1)×10(3) vs (23.3 ± 2.0)×10(3) and (25.7 ± 1.8)×10(3) U/L).

CONCLUSION

Compound Xueshuantong Capsule may decrease proteinuria through its suppression of oxidative stress and not its improvement of ECM metabolism.

[Effect of dibutyl phthalate and di-(2-ethylhexyl) phthalate on urine SOD activity and MDA content in rats]

OBJECTIVE

To evaluate the effect of dibutyl phthalate (DBP) and di-(2-ethylhexyl) phthalate (DEHP) on urine superoxide dismutase (SOD) activity and malondialdehyde (MDA) content in rats.

METHODS

According to 2×2 factorial analysis, 60 adult male SD rats were randomized into 10 groups (n=6), including a control group (fed with sesame oil), 3 DBP groups (fed with DBP at the doses of 30, 100 and 300 mg/kg), 3 DEHP groups (with DEHP at 50, 150, and 450 mg/kg), and 3 DBP+DEHP groups (with 30 mg/kg DBP+50 mg/kg DEHP, 100 mg/kg DBP+150 mg/kg DEHP, and 300 mg/kg DBP +450 mg/kg DEHP). The agents were administered in a single dose through gavage in a volume of 2 ml. After the treatments, the 24, 48, 72, and 96 h urine samples were collected to determine the SOD activity and MDA content.

RESULTS

DBP and DEHP, either alone or in combination, significantly decreased SOD activity and increased MDA content in the urine collected at 24 h but not at the other time points. Such changes were gradually reversed with time.

CONCLUSION

DBP or DEHP treatment alone can result in significant oxidative damage in the kidney of rats, and the toxic effect of the combined exposure is even more obvious.

Comprehensive characterization of serum clinical chemistry parameters and the identification of urinary superoxide dismutase in a carbon tetrachloride-induced model of hepatic fibrosis in the female Hanover Wistar rat

Carbon tetrachloride (CCl(4)) was used to induce liver fibrosis in the rat. Using this model, we have identified changes in serum and urinary clinical chemistry parameters, and characterized histopathological lesions in the liver. Two experiments were conducted. In Experiment 1, rats were dosed at six levels of CCl(4) (0.06-0.36 ml/kg) twice weekly for 6 weeks, followed by a 6-week non-dosing recovery period (week 12). Livers were removed for histology at 6 and 12 weeks and serum parameters analysed. In Experiment 2, rats were given seven dose levels of CCl(4) (0.4-1.0 ml/kg) twice weekly for 6 weeks, followed by a 6-week recovery period (week 12); urine samples were analysed at 3, 6, 9 and 12 weeks using one-dimensional sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). Liver fibrosis was evident at 6 weeks in Experiments 1 and 2, and the activity of serum enzymes (including alanine aminotransferase, aspartate aminotransferase and glutamate dehydrogenase) was increased. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis (Experiment 2) revealed a protein band at 18.4 kDa in urine from rats treated with CCl(4), not present in control urine, which was identified as copper/zinc superoxide dismutase (Cu/Zn SOD). Western blotting revealed that SOD was increased in urine from rats treated with CCl(4) at 3 and 6 weeks, but not at 9 and 12 weeks. We conclude that Cu/Zn SOD is a urinary marker of hepatic necrosis, but not hepatic fibrosis.

The effects of oxidative stress in urinary tract infection during pregnancy

The purpose of this study was to determine the effect of urinary tract infection (UTI) on antioxidant systems and lipid peroxidation (LPO) levels during pregnancy. We also investigated if these antioxidant systems and LPO levels differed in each trimester. One hundred forty-three nonpregnant women, as a control group, and 77 pregnant women were included in the study. Urine cultures were performed according to standard techniques. Catalase (CAT), superoxide dismutase (SOD), and LPO levels were measured using a spectrophotometer. UTI was observed in 14 of 77 pregnant women and the isolated microorganisms were Escherichia coli, Klebsiella pneumoniae, and Staphylococcus saprophyticus. CAT, SOD, and LPO levels were increased in pregnant women compared with nonpregnant women (P < .01). CAT, SOD activities, and LPO levels were increased from the first trimester to the third trimester in pregnancy without UTI. However, CAT and SOD activities were decreased, LPO levels were increased from the first trimester to the third trimester in pregnancy with UTI (P < .01). Pregnancy causes oxidative stress and also UTI during pregnancy may aggravate oxidative stress.

The effects of oxidative stress in urinary tract infection

We aimed to determine the effects of oxidative stress in urinary tract infection (UTI). One hundred sixty-four urine samples obtained from patients with the prediagnosis of acute UTI admitted to the Faculty of Medicine, Kahramanmaras Sutcu Imam University, were included in this study. Urine cultures were performed according to standard techniques. Urinary isolates were identified by using API ID 32E. The catalase and superoxide dismutase activity and the lipid peroxidation levels known as oxidative stress markers were measured in all urine samples. Thirty-six pathogen microorganisms were identified in positive urine cultures. These microorganisms were as follows: 23 (63.8%) E coli, 5 (13.8%) P mirabilis, 4 (11.1%) K pneumoniae, 2 (5.5%) Candida spp, 1 (2.7%) S saprophyticus, and 1 (2.7%) P aeruginosa. It was observed that lipid peroxidation levels were increased while catalase and superoxide dismutase activities were decreased in positive urine cultures, compared to negative cultures. We conclude that urinary tract infection causes oxidative stress, increases lipid peroxidation level, and leads to insufficiency of antioxidant enzymes.

Trace element status in Saudi patients with established atherosclerosis

BACKGROUND

Traditional coronary risk factors do not fully explain variations in the incidence of cardiovascular disease (CVD). Epidemiological studies have implicated perturbations in selenium, copper, and zinc metabolism in the aetiology of CVD. However, these studies have been principally undertaken in Caucasian populations, in whom trace element intake is generally sufficient.

METHOD

We have measured serum and urine selenium, copper, and zinc; and superoxide dismutase, glutathione peroxidase, and lipid peroxide concentrations in 130 Saudi male subjects with established CVD, and 130 age-matched controls.

RESULTS

Diabetes mellitus, positive smoking habit (p<0.0001 for both), and hypertension (p<0.05) were more prevalent among CVD patients. Urinary copper (p<0.0001) and zinc (p<0.05) were higher among controls. Serum selenium concentrations were lower among CVD patients (p<0.001), and a high proportion (52%) had selenium levels below 79mug/L compared to controls (22%) (p<0.0001). Conditional logistic regression analysis, showed the characteristics differentiating CVD patients from controls were serum zinc (odds ratio (OR) 0.92, confidence interval (CI) 0.85-0.99, p<0.05), serum copper/zinc ratio (OR 0.31, CI 0.10-0.96), serum selenium (OR 0.07, CI 0.02-0.31, p<0.0001), and urine selenium (OR 3.34, CI 1.40-7.99, p<0.01).

CONCLUSION

Measures of trace metals status appear to be associated with the risk of atherosclerosis in a Saudi male population.

Immunohistochemical study of myoglobin and oxidative injury-related markers in the kidney of methamphetamine abusers

It is known that methamphetamine (MA) causes rhabdomyolysis, myoglobinuria, and acute renal failure. We conducted an immunohistochemical study on the kidney of 22 forensic autopsy cases in which MA had been detected. Myoglobin was positive in 17 cases. The concentration of the blood MA in the myoglobin-positive cases (8.39+/-3.43 micromol/dl) was higher than -negative cases (0.198+/-0.076 micromol/dl). And, the 70 kDa heat shock protein (HSP70), 8-hydroxy-2'-deoxyguanosine (8-OH-dG), 4-hydroxy-2-nonenal (4-HNE), and Cu/Zn superoxide dismutase (SOD) were also stained positively in five, ten, 11, nine cases of examined, respectively. In addition, 80% of HSP70-positive cases were myoglobin-positive. Myoglobin was also observed in 60% of 8-OH-dG-positive, in 82% of 4-HNE-positive, and in 78% of SOD-positive cases, respectively. Therefore, myoglobin rather than MA itself might induce oxidative damage. From these results, it was considered that MA abuse had caused the skeletal muscle damage before death. In forensic autopsy cases of drug abusers, the antemortem situation is not often known. The present research suggested that in addition to the measurement of the concentration of MA, immunohistochemical staining of myoglobin, HSP70, 8-OH-dG, 4-HNE, and SOD offers important information for the diagnosis of MA poisoning.

[Circadian rhythms of urinary parameters in children with glomerulonephritis]

Circadian rhythms of urinary parameters were studied in healthy children and those with glomerulonephritis. In healthy children, urinary excretion of many substances rhythmically varied during a day. Variations were related to the volume and specific gravity of urine, to the levels of creatinine, MDA, and SOD activities. Children with glomerulonephritis showed changes in values of circadian rhythm of urine parameters. These disorders included changes in circadian variations and mean daily values, inversion of group and individual excretion patterns, which indicates that there is an external and internal disagreement of biological rhythms in children with glomerulonephritis.

Increase of urinary extracellular-superoxide dismutase level correlated with cyclic adenosine monophosphate

Extracellular superoxide dismutase (EC-SOD) is a secretory protein that is the major SOD isozyme in extracellular fluids. Plasma EC-SOD levels are distributed in two discrete groups with the rare group having an enzyme with glycine instead of arginine-213, which causes a 10-fold higher serum level. Within the common phenotype group, the urinary EC-SOD level was significantly correlated with the urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG), but not with serum EC-SOD. EC-SOD appears not to be leaked from the plasma by glomerular filtration, but rather to be secreted from the renal tubule or its surrounding tissues. The urinary EC-SOD level was also significantly correlated with the urinary cyclic adenosine monophosphate (cAMP) level. cAMP analogues and adenylate cyclase modulators significantly stimulated the expression of EC-SOD but not other SOD isozymes in cultured fibroblast cell lines. Moreover, injection of parathyroid hormone, in Ellsworth-Howard tests, increased urinary EC-SOD accompanied with the elevations of urinary cAMP and NAG. Together these observations suggest that factor(s) that stimulate the adenylate cyclase-cAMP system regulate the urinary EC-SOD level.

Enzyme immunoassay for cuprozinc-superoxide dismutase in whole blood and urine during head down bed rest

A highly sensitive enzyme immunoassay system for the determination of cuprozinc-superoxide dismutase (Cu, Zn-SOD) in whole blood and urine with horseradish peroxidase as a labeling enzyme was reported. It measures Cu, Zn-SOD with good repeatability of 0.05-5 ng. Coefficients of variation were 1.17%-7.94% for within-a-day assay and 1.94%-10.73% for between days assay. The average recoveries from whole blood and urine were 101.0%-113.8% and 96.0%-116.0%, respectively. Using this enzyme immunoassay, the normal range of Cu, Zn-SOD concentration in the whole blood was found to be 281.66 +/- 25.45ng/ml, and it tended to decline 3d after HDBR -6 degrees. The normal range in urine Cu, Zn-SOD concentration was 0.87 +/- 0. 33 micrograms/g of creatinine, it decreased significantly on the 3rd day during HDBR -6 degrees. Both of them recovered to normal on the 6th day during HDBR -6 degrees.

Safety and pharmacokinetics of recombinant human superoxide dismutase administered intratracheally to premature neonates with respiratory distress syndrome

OBJECTIVE

As a first step in the evaluation of recombinant human CuZn superoxide dismutase (rhSOD) in the prevention of neonatal lung injury, safety and pharmacokinetics of intratracheally (IT) administered rhSOD were studied.

METHODS

Twenty-six preterm infants weighing 750 to 1250 g with respiratory distress syndrome were studied in three sequential groups (placebo, 0.5, and 5 mg/kg). Placebo or rhSOD was administered IT 30 minutes after the first surfactant dose. Serial blood and urine studies, rhSOD levels, tracheal aspirate fluid (TAF) markers of acute inflammation, radiographs, and ultrasounds were performed over the 28-day study period.

RESULTS

Serum SOD concentrations were similar at baseline for all three groups (geometric mean 0.2, upper-lower limit 0.1 to 0.2 microgram/mL). In the 0.5-mg/kg group, levels were highest at 12 hours (geometric mean 0.7, upper-lower limit 0.5 to 0.8 microgram/mL) and returned to baseline by day 3. In the 5-mg/kg group, levels were highest at 6 hours (geometric mean 3.0, upper-lower limit 2.3 to 4.0 micrograms/mL) and returned to baseline by day 4. Concentrations of SOD in TAF were also similar at baseline for all three groups (geometric mean 0.2, upper-lower limit 0.2 to 0.3 microgram/mL). There were no significant increases in the placebo group, but levels in the 0.5-mg/kg group were highest when first sampled at 24 hours (geometric mean 1.1, upper-lower limit 0.8 to 1.4 micrograms/mL) and returned to baseline by day 3. In the 5-mg/kg group, levels were also highest when sampled at 24 hours (geometric mean 1.4, upper-lower limit 0.9 to 2.1 micrograms/mL) and returned to baseline by day 4. Urine levels were highest at 12 hours in both the 0.5-mg/kg (geometric mean 1.3, upper-lower limit 1.0 to 1.7 micrograms/mL) and 5-mg/kg infants (geometric mean 6.4, upper-lower limit 3.9 to 10.4 micrograms/mL) and decreased significantly by day 2 to 3. rhSOD activity assays (serum, TAF, and urine) demonstrated that the enzyme still possessed significant activity. No adverse effects of rhSOD were found. TAF neutrophil chemotactic activity and albumin concentrations, important acute lung injury markers, were significantly lower in the high-dose rhSOD group compared with the other groups.

CONCLUSIONS

Data suggest that a single IT dose of rhSOD results in significant increases in both concentration and activity of the antioxidant in serum, TAF, and urine for 2 to 3 days. The enzyme appears to be well tolerated, and TAF inflammatory markers are reduced after administration. This has important implications in rhSOD trials to prevent acute and chronic lung injury in preterm neonates.

Effect of massotherapy on the in vivo free radical metabolism in patients with prolapse of lumbar intervertebral disc and cervical spondylopathy

The endogenous free radical scavenger superoxide dismutase (SOD) and blood catalase (CAT) in 2 groups of patients with prolapse of lumbar intervertebral disc and cervical spondylopathy were lower than that of the healthy control group, while the -SH reflecting the metabolic disturbance of free radical was higher. After massotherapy, blood SOD and CAT were increased, while lipid peroxide (LPO), -SH in urine were decreased, demonstrating that there are distinct parallel relationships existing in the changes of these enzymes in blood and urine.

Quantitative and qualitative changes of extracellular-superoxide dismutase in patients with various diseases

Extracellular-superoxide dismutase (EC-SOD) is a secretory glycoprotein that is the major SOD isozyme in extracellular fluids. It has previously been shown that EC-SOD levels in sera from healthy persons are clearly divided into two discontinuous groups: a lower group (named Group I, below 120 ng/ml) and a higher group (Group II, above 400 ng/ml). The family studies have shown that the high EC-SOD level in healthy persons is genetically transmitted. We report here on the EC-SOD levels in the sera of patients with various diseases. The EC-SOD levels were distinctly higher in patients with renal diseases and moderately higher in liver diseases and diabetes than those in normal healthy persons. In cerebrovascular diseases, heart diseases and acute digestive diseases, significant differences of EC-SOD were not observed. In patients with renal diseases, the increase of EC-SOD was accompanied by the lack of renal function. Serum EC-SOD in Group I healthy persons is known to be heterogeneous with regard to heparin affinity and can be separated into three fractions: A without affinity, B with weak affinity and C with relatively strong heparin affinity, whereas the EC-SOD in Group II is mainly one fraction of C-type. Also in the case of hemodialysis patients, serum EC-SOD in Group I or Group I' (approximately 120-400 ng/ml) was divided into three fractions. EC-SOD in Group II showed two different profiles on heparin-Sepharose column chromatographies: one consisted mainly of EC-SOD C and the other consisted of EC-SOD A and C. It is probable that the high serum EC-SOD level in hemodialysis patients was due to two possible factors: the genetic transmitted factor and unknown pathophysiological factor(s).

Manipulation of renal disposition of human recombinant superoxide dismutase by chemical modification

The renal disposition characteristics of superoxide dismutase (SOD) and its derivatives, including macromolecular conjugates with polyethylene glycol and carboxymethyl-dextran, a cationized derivative, and glycosylated derivatives with galactose and mannose, were studied in the isolated perfused rat kidney. Renal disposition processes, such as glomerular filtration, tubular reabsorption, and uptake from the capillary side, were quantitatively determined by single-pass indicator dilution experiments under filtering and nonfiltering kidney conditions. Native SOD had a high glomerular filtration rate (40% of that of inulin) and was effectively reabsorbed in the tubules, while no significant uptake was observed from capillary side. Macromolecular conjugates showed restricted glomerular filtration due to an increase in molecular size. Cationization of SOD greatly enhanced its association with the tissue, not only from the luminal side but also from the capillary side, based upon electrostatic interaction. Galactosylated and mannosylated SOD showed reduced tubular reabsorption and increased exposure of the luminal surface to the enzyme. In addition, a small but significant uptake of mannosylated SOD from the capillary side was observed. This uptake was dose-dependent and completely inhibited by mannan, suggesting that mannose receptor-mediated endocytosis existed in the capillary side of the kidney. Thus, we can manipulate the renal disposition profiles of SOD by changing its physicochemical or biological properties through chemical modification.

Disposition characteristics of protein drugs in the perfused rat kidney

The renal disposition characteristics of 111In-labeled neocarzinostatin (NCS), soybean trypsin inhibitor (STI), and superoxide dismutase (SOD) were studied in the perfused rat kidney. In a single-pass indicator dilution experiment, venous and urinary recovery profiles and tissue accumulation of proteins were determined under filtering or nonfiltering conditions. In the nonfiltering kidney perfusion experiment, no significant tissue accumulation was observed, suggesting minimal uptake from the glomerular and peritubular capillary sides. Therefore, tissue recovery corresponded to that with tubular reabsorption after glomerular filtration. The total amount of NCS or STI being filtrated through glomeruli, the sum of tissue and urinary recoveries, was similar to that of inulin, but that of SOD was about half. Similarly, the steady-state distribution volumes (Vd) of NCS and STI obtained by moment analysis of their venous outflow curves were similar to that of inulin, while the Vd value of SOD was significantly lower. These results suggest the restricted passage of SOD through the glomerular and postglomerular capillary wall. The tubular reabsorption ratio of proteins against the total filtrated amount decreased with an increase in the administered dose, suggesting nonlinearity of reabsorption. SOD had the largest reabsorption ratio. Thus, this experimental system is useful for quantitative analysis of renal disposition of proteins.

Manganese-containing superoxide dismutase in blood and urine during open-heart surgery

Concentrations of Manganese-containing superoxide dismutase (Mn-SOD) were measured perioperatively by enzyme immunoassay in serial samples of arterial and coronary sinus blood and urine taken from 18 patients undergoing mitral valve surgery. The mean Mn-SOD concentration in the arterial blood samples was 66.2 (SD 16.1 ng/ml) at induction of anesthesia, increased gradually after reperfusion and peaked on the 2nd post-operative day [150 (SD 58.3) ng/ml]. The mean concentration of Mn-SOD in the coronary sinus blood samples was significantly higher than in the arterial samples only at the 6th hour after reperfusion [97 (SD 21.8) ng/ml vs 90.3 (SD 20.9) ng/ml, p < 0.05]. Although concentrations of Mn-SOD in blood did not increase in 8 patients who underwent midline sternotomy for a mediastinal tumor, they increased dramatically in 3 patients who sustained a perioperative myocardial infarction. During open heart surgery the peak values of plasma Mn-SOD concentrations were correlated to that of plasma creatine kinase-MB concentrations (r = 0.5532, n = 18, p < 05) and cardiac ischemic period (r = 0.5186, n = 18, p < 05). Although the meaning of an increase in plasma Mn-SOD concentrations during open heart surgery is not clarified, it may be released from the heart and anywhere also in the body damaged during cardiopulmonary bypass.

Quantitative analysis of extracellular-superoxide dismutase in serum and urine by ELISA with monoclonal antibody

The superoxide anion has been implicated in a wide range of diseases. The major protector against superoxide anion in the extracellular space is extracellular-superoxide dismutase (EC-SOD). EC-SOD is the major SOD isozyme in plasma and forms an equilibrium between the plasma phase and heparan sulfate proteoglycan on the surface of the endothelium. An ELISA method for the measurement of human EC-SOD with monoclonal antibody was established. The proposed method had a high sensitivity (assay range, 0.05-50 ng/ml), good recovery (recovery percentage, 96.9 +/- 5.6%) and reproducibility (within-day assay, C.V. = 8.6-10.2%; between-day assay, C.V. = 6.5-11.7%). EC-SOD levels in sera from healthy persons are clearly divided into two groups: a lower group (Group I, below 120 ng/ml, n = 146) and higher group (Group II, above 400 ng/ml, n = 10). The EC-SOD in Group I were almost normally distributed and the mean level was 55.8 +/- 18.8 ng/ml. The serum EC-SOD level assayed by ELISA correlated well with serum SOD activity. The serum EC-SOD in Group I is heterogeneous with regard to affinity for heparin-Sepharose and could be separated into three approximately equal fractions, whereas the EC-SOD in Group II is mainly one fraction with a high affinity for the column. The apparent molecular weight and carbohydrate structure of serum EC-SOD in Group II are identical to those in Group I. The high EC-SOD level in sera from some individuals may reflect the excessive stimulation of EC-SOD synthesis in vivo or the growth of selected cells in vivo, because EC-SOD is known to be expressed by a few cell types in vivo as a high-heparin-affinity subtype.

Early detection of changes in kidney function in workers exposed to solvents and heavy metals

Increases in urine concentration of specific proteins have been proposed as early indicators of deleterious changes in kidney function. Four urinary proteins (albumin, superoxide dismutase, transferrin and N-acetyl-beta-D-glucosaminidase) were measured in workers exposed to heavy metals and solvents. None of the workers had clinical evidence of renal disease or hypertension. Workers exposed to mercury had a significant increase in urinary transferring, superoxide dismutase levels were slightly increased in workers exposed to solvents and lead, follow-up of these workers is needed to confirm that these changes predict late clinical deterioration of kidney functions.

An enzyme immunoassay for cuprozinc superoxide dismutase using monoclonal antibodies. Application for pharmacokinetic study

We developed an enzyme immunoassay for determining human cuprozinc superoxide dismutase (h-SOD) using two kinds of monoclonal antibodies prepared by immunizing h-SOD to BALB/c mice. This method was sensitive and specific enough to determine exogenous h-SOD injected into rats. When intravenously injected into rats, much of the immunoreactive h-SOD accumulated in the kidney and was rapidly excreted in the urine. We observed both a modified and an unmodified form of exogenous h-SOD in rat urine.

Safety evaluation of free radical scavengers PEG-catalase and PEG-superoxide dismutase

Treatment with catalase and SOD (superoxide dismutase) could diminish the damage due to oxygen free radical formation, but these enzymes are rapidly removed from circulation. The covalent attachment of monomethoxypolyethylene glycol (PEG) to catalase and SOD extended their plasma half-lives. Toxicity of PEG-catalase and PEG-SOD was evaluated in mice and rats prior to their use as free radical scavengers. Rodents used in acute, subacute, and subchronic toxicologic studies could tolerate large doses of PEG-catalase and PEG-SOD without developing toxic signs. The conjugates did not affect survival rate, appearance, behavior, food intake, blood chemistry, hematology, or urinalysis. In general, body weight gains, organ weights, and histomorphology were also unaffected. Massive doses of PEG-catalase caused slight weight loss, splenic hypertrophy, and generalized splenic stimulation in mice. Massive doses of PEG-SOD resulted in vacuolation in splenic macrophages in rats. PEG-catalase and PEG-SOD circulated for 3 days and 8 days, respectively, in mice following i.v. or i.m. administration.

Evidence against a role for superoxide ions in the injury of nephrotoxic nephritis in rats

The accelerated model of nephrotoxic serum nephritis (NTSN) was produced in 12 Sprague-Dawley rats. Six of these rats were administered superoxide dismutase (EC 1.15.1.1; SOD) subcutaneously (8 mg/kg) 8-hourly for 4 days. The first dose was given 6 h before the nephrotoxic serum (NTS). The progression of renal disease was monitored by following (i) albumin excretion, (ii) serum creatinine and creatinine clearance and (iii) renal histopathology and immunofluorescence. There was no evidence that SOD influences the course of NTSN. SOD was scarcely excreted by control rats or rats with NTSN.