Effect of N‐Acetylcysteine on Antioxidant Status in Glycerol‐Induced Acute Renal Failure in Rats

Myoglobinuric acute renal failure has three pathogenic mechanisms: tubular obstruction, renal vasoconstriction, and oxidative stress. The latter is generated through the iron released from the group hemo of the myoglobin. Iron induces the formation of high‐activity oxygen free radicals that increase oxidative stress and provoke lipid peroxidation and cellular death. This oxidative stress can be measured in several ways, both total or partially with the total antioxidant status or the intermediate enzymes. On the other hand, N‐acetylcysteine is a demonstrated substance with antioxidant properties. The aim of the present work was to assess the effect of N‐acetylcysteine on the oxidative stress in the glycerol‐induced acute renal failure in rats model. We observed that the animals treated with N‐acetylcysteine showed an improvement in the antioxidant activity given by an increase in the total antioxidant status and glutathione reductase levels in serum. This improvement was greater when treatment was administered before the induction of rhabdomyolysis. Nevertheless, the observed increase in antioxidant status was only statistically significant for glutathione reductase but not for total antioxidant status. Our results support an important role for N‐acetylcysteine in the treatment of this form of acute renal failure, although we think that oxidative stress is not the main pathogenic mechanism of the tubular necrosis induced by rhabdomyolysis, tubular obstruction and renal vasoconstriction being still more important.     

Study of the activity of glutathione-peroxidase,glutathione-transferase,and glutathione-reductase in renal transplants

The aim of this work was to study the temporare variation of oxidative stress in the plasma and erythrocytes (CR) of renal transplant patients We determined total glutathione (GST), as well as oxidized (GSSG) and reduced (GSH) fractions and the activity of glutathione peroxidase (G-px), glutathione reductase (G-red) and glutathione transferase (GSt). Determinations were performed 48 hours before transplant as well as 1 and 2 weeks after the renal transplant. The results showed a high "oxidative stress" rate, resulting from the equilibrium between the production of free radicals and the activity of antioxidants, the former being higher proportionally. Immediately after the transplant, there was an increase in oxidative stress, which resulted in an increased G-red, a marked decrease in plasma and in erythrocyte G-px (CR9 and an abrupt drop both in GST levels in plasma and in GSG (as well as in the [GSH]/[GSSG] relationship). Thereafter there was a significant improvement in the activity of antioxidant enzymes, but without normalization; the total glutathione levels and the activity of various enzymes approached the average values of the control group.     

Postoperative acute renal failure secondary to rhabdomyolysis from exaggerated lithotomy position.

Perioperative renal dysfunction is a common problem following urogenital surgery. The most common causes of renal failure include ischemic or nephrotoxic acute tubular necrosis, renal vascular injury, and urinary tract obstruction. This case conference describes a patient who developed acute renal failure, secondary to rhabdomyolysis after a 7-hour urologic surgical procedure in an exaggerated lithotomy position. Early diagnosis and aggressive treatment are essential to prevent or limit the severity of acute renal failure. A review of the literature and pathophysiology of acute renal failure secondary to rhabdomyolysis is included.     

Glutathione determination and a study of the activity of glutathione-peroxidase,glutathione-transferase,and glutathione-reductase in renal transplants

The aim of this work is to study the temporary variation of oxidative stress in renal transplants, both in plasma and in erythrocytes (CR). In order to do so, we determined total glutathione (GST) levels, both oxidized (GSSG) and reduced (GSH), and the activity of enzymes, glutathione peroxidase (G-px), glutathione reductase (G-red) and glutathione transferase (GSt), in renal transplant patients. Determinations were made 48 h before the transplant 1 week and 2 weeks after the renal transplant. The results obtained confirm a high "oxidative stress" rate, resulting from the equilibrium between the production of free radicals and the activity of antioxidants, the former being higher proportionally. Immediately after the transplant there is an increase of oxidative stress, which results in an increase of G-red, a marked decrease of G-px in plasma and in erythrocytes (CR) and an abrupt drop both in GST levels in plasma and in GSG (as well as in the [GSH]/[GSSG] relationship). As times goes on, after the transplant, there is a significant improvement in the activity of antioxidant enzymes, but there is no normalization, which is easily seen in the fact that total glutathione levels and the activity of the various enzymes approach the average values of the control group.     

GLUTATHIONE DETERMINATION AND A STUDY OF THE ACTIVITY OF GLUTATHIONE-PEROXIDASE,GLUTATHIONE-TRANSFERASE,AND GLUTATHIONE-REDUCTASE IN RENAL TRANSPLANTS

The aim of this work is to study the temporary variation of oxidative stress in renal transplants, both in plasma and in erythrocytes (CR). In order to do so, we determined total glutathione (GST) levels, both oxidized (GSSG) and reduced (GSH), and the activity of enzymes, glutathione peroxidase (G-px), glutathione reductase (G-red) and glutathione transferase (GSt), in renal transplant patients. Determinations were made 48 h before the transplant 1 week and 2 weeks after the renal transplant. The results obtained confirm a high “oxidative stress” rate, resulting from the equilibrium between the production of free radicals and the activity of antioxidants, the former being higher proportionally. Immediately after the transplant there is an increase of oxidative stress, which results in an increase of G-red, a marked decrease of G-px in plasma and in erythrocytes (CR) and an abrupt drop both in GST levels in plasma and in GSG (as well as in the [GSH]/[GSSG] relationship). As times goes on, after the transplant, there is a significant improvement in the activity of antioxidant enzymes, but there is no normalization, which is easily seen in the fact that total glutathione levels and the activity of the various enzymes approach the average values of the control group.     

Interactions between serum creatinine, volume status, N-acetylcysteine, and contrast-induced nephropathy

Contrast-induced nephropathy is reported to be the third leading cause of acute renal failure. The development of contrast-induced nephropathy is associated with prolonged hospitalization, the potential need for renal replacement therapy, and increased mortality. N-acetylcysteine is commonly used for the prevention of contrast-induced nephropathy despite inconsistent results from numerous clinical trials and meta-analyses. The advantage of N-acetylcysteine in most studies was based on a decrease in the serum creatinine concentration and a decrease in oxidative stress. N-acetylcysteine itself can directly lower serum creatinine concentration without improving renal function, and hypovolemia can affect the oxidative stress. In most of the N-acetylcysteine studies, there are a lack of volume status and secondary end points. The value of N-acetylcysteine for the prevention of contrast-induced nephropathy seems questionable. The interactions between serum creatinine, N-Acetylcysteine, volume status, and the development of contrast-induced nephropathy were discussed in this letter.     

Treatment With N-Acetylcysteine in Stable Renal Transplantation

The primary cause of morbidity and mortality in renal transplantation is cardiovascular disease. Increased oxidative stress implies a greater degree of atherogenesis in these patients. N-acetylcysteine (NAC) which has a thiol group that is the source of l-cysteine and reduced glutathione, acts against atherosclerosis via a decrease in apoptosis, vasoconstriction, and endothelial dysfunction. Experimental models have examined the antioxidant effects of NAC during and after ischemia-reperfusion, but few studies have shown an effect in renal transplantation in human beings. In 8 months, we studied the effect of NAC treatment on oxidative stress, lipids, and renal function in 25 patients with stable renal function and no diabetes after transplantation. Data were collected on oxidative parameters: malondialdehyde, glutathione peroxidase, catalase, superoxide dismutase, glutathione reductase, lipid profile, and renal function (creatinine concentration, Cockroft-Gault formula, and Modified Diet in Renal Disease study). There were no significant differences in oxidative profile before and after treatment with NAC. The mean serum high-density lipoprotein cholesterol fraction increased after treatment and showed a significant positive correlation with glutathione peroxidase (r = 0.495). Serum creatinine concentration decreased, and Cockroft-Gault and Modified Diet in Renal Disease study estimates of renal function increased in the treatment period. In conclusion, NAC treatment in patients with stable renal function after transplantation increased high-density lipoprotein cholesterol and antioxidant molecules in relation to glutathione peroxidase, with a positive influence on renal function.     

Modulation factors of oxidative status in stable renal transplantation

Reactive oxygen species (ROS) trigger a biomolecular alteration that causes functional and structural changes. In renal transplantation, there is an increase in oxidative phenomena related to endothelial dysfunction, inflammation, and atherosclerosis, the main cause of cardiovascular complications and chronic allograft failure. The present study was designed to assess the oxidative state of transplant patients with stable renal function, in order to establish differences in oxidative, biochemical, and clinical parameters between patients treated with tacrolimus versus cyclosporine. We studied 67 stable kidney transplant patients treated with calcineurin inhibitors who were not receiving cholesterol-lowering therapy, and 14 healthy subjects. Data were collected on biochemical parameters: lipid profile (apoA, apoB, total cholesterol and fractions, and triglycerides); urea; and creatinine; oxidative parameters: malondialdehyde (MDA) as a lipid peroxidation marker, glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD), glutathione reductase (GR), and antibodies against oxidized LDL; and clinical variables. Transplanted patients showed a higher oxidative status (MDA increase and GPx decrease) than healthy subjects. The oxidative status did not differ between the cyclosporine and tacrolimus cohorts. Some factors during the posttransplant period, such as delayed graft function, cytomegalovirus infection, and microalbuminuria, which may damage renal function, produce a decreased antioxidant capacity (lower GPx).     

Letter to the Editor: “Interactions between Serum Creatinine,Volume Status,N-Acetylcysteine,and Contrast-Induced Nephropathy”

Contrast-induced nephropathy is reported to be the third leading cause of acute renal failure. The development of contrast-induced nephropathy is associated with prolonged hospitalization, the potential need for renal replacement therapy, and increased mortality. N-acetylcysteine is commonly used for the prevention of contrast-induced nephropathy despite inconsistent results from numerous clinical trials and meta-analyses. The advantage of N-acetylcysteine in most studies was based on a decrease in the serum creatinine concentration and a decrease in oxidative stress. N-acetylcysteine itself can directly lower serum creatinine concentration without improving renal function, and hypovolemia can affect the oxidative stress. In most of the N‐acetylcysteine studies, there are a lack of volume status and secondary end points. The value of N-acetylcysteine for the prevention of contrast-induced nephropathy seems questionable. The interactions between serum creatinine, N-Acetylcysteine, volume status, and the development of contrast-induced nephropathy were discussed in this letter.     

Oxidative stress in chronic renal failure

This study focuses on the oxidative stress in patients with severe chronic renal failure who are not undergoing dialysis treatment. The erythocyte levels, creatinine clearing and plasma- and cell activities of the following enzymes were determined: glutathione peroxidase (Gpx), superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), and glutathione transferase (GT). The concentrations of non-enzyme molecules such as total glutathione in both oxidized and reduced forms, and malonyldialdehyde (MDA) were also measured. The obtained values were compared with those in healthy blood donors of comparable age and social status. The results indicate that chronic renal patients have lower glutathione levels and reduced activities of glutathione peroxidase and of glutathione reductase, while exhibiting elevated levels of malonyldialdehyde and activities of superoxide dismutase, glutathione transferase, and catalase. Finally, creatinine clearing was found to be correlated (p < 0.001) to total (oxidized and reduced) glutathione, Gpx and MDA. These observations may serve to establish a simple protocol for evaluation of renal function.     

Amelioration of myoglobinuric renal damage in rats by chronic exposure to flavonol-rich red wine.

BACKGROUND: Myoglobinuric acute renal failure causes increased oxidative stress. Since ethanol upregulates renal antioxidant enzymes and wine polyphenols behave as antioxidants, we tested the hypothesis that red wine components would ameliorate the renal damage caused by rhabdomyolysis. METHODS: Adult rats received water (control), alcohol-free red wine, ethanol 12.5% (v/v) or red wine for 10 weeks. Rhabdomyolysis was induced by glycerol injection (50%, 10 ml/kg, i.m.), and urine and blood samples were collected 6 h later to measure renal function parameters, creatine kinase (CK) activity, free F(2)-isoprostanes and total antioxidant capacity. Kidneys were then harvested for morphological studies and determinations of lipid peroxidation, protein carbonylation, (Na + K)-ATPase and antioxidant enzyme activities. RESULTS: In the control group, myoglobinuria was associated with a 68% decrease in creatinine clearance and increases in plasma creatinine and blood urea nitrogen of 3.2 and 1.8 times above baseline, respectively. Controls also showed increases in plasma free F(2)-isoprostanes levels and CK activity, together with enhanced renal expression of the antioxidant enzymes catalase, glutathione peroxidase and superoxide dismutase, as well as increased production of malondialdehyde and carbonyls. Rhabdomolysis reduced renal (Na + K)-ATPase activity and this reduction was associated with a 5-fold increase in fractional sodium excretion as well as morphological damage to the kidney. These changes were significantly attenuated by pretreatment with chronic red wine exposure prior to glycerol injection. A less marked degree of functional and biochemical protection was also observed in response to the administration of alcohol-free red wine and ethanol. CONCLUSIONS: The present data suggest that red wine protects against functional, biochemical and morphological damage caused by rhabdomyolysis in the rat, and this protection may be due to the synergistic effects of ethanol and non-alcoholic red wine components.     

Effects of melatonin administration to rats with glycerol-induced acute renal failure

Melatonin, the pineal hormone with antioxidative properties was administered to rats with glycerol-induced myoglobinuric acute renal failure (Gly-ARF). This model is characterized by acute tubular necrosis mediated by heme-iron oxidative stress. Rats received melatonin (20 mg/kg) concomitant and 3 h after glycerol injection. Gly-ARF rats showed at 24 h a 78% reduction in glomerular filtration rate, whereas this decrement was significantly reduced to 35% in the melatonin treated Gly-ARF rats. Tubular function evaluated by tubular reabsorption of sodium and lithium was also preserved in melatonin treated rats. The histologic analysis revealed extensive cortical tubular necrosis that was significantly reduced by melatonin treatment. The renal concentration of malondialdehyde (MDA) was increased 6 h after glycerol injection in Gly-ARF and this elevation was prevented when melatonin was administered. Renal concentration of reduced glutathione (GSH) was decreased at 6 h in Gly-ARF and melatonin did not reverse this decrease. It was concluded that melatonin administration attenuated the renal injury in the glycerol model of acute renal failure and reduced kidney oxidative stress through a GSH-independent mechanism.     

EFFECTS OF MELATONIN ADMINISTRATION TO RATS WITH GLYCEROL-INDUCED ACUTE RENAL FAILURE

Melatonin, the pineal hormone with antioxidative properties was administered to rats with glycerol-induced myoglobinuric acute renal failure (Gly-ARF). This model is characterized by acute tubular necrosis mediated by heme-iron oxidative stress. Rats received melatonin (20 mg/kg) concomitant and 3 h after glycerol injection. Gly-ARF rats showed at 24 h a 78% reduction in glomerular filtration rate, whereas this decrement was significantly reduced to 35% in the melatonin treated Gly-ARF rats. Tubular function evaluated by tubular reabsorption of sodium and lithium was also preserved in melatonin treated rats. The histologic analysis revealed extensive cortical tubular necrosis that was significantly reduced by melatonin treatment. The renal concentration of malondialdehyde (MDA) was increased 6 h after glycerol injection in Gly-ARF and this elevation was prevented when melatonin was administered. Renal concentration of reduced glutathione (GSH) was decreased at 6 h in Gly-ARF and melatonin did not reverse this decrease. It was concluded that melatonin administration attenuated the renal injury in the glycerol model of acute renal failure and reduced kidney oxidative stress through a GSH-independent mechanism.     

Renal effects of N-acetylcysteine in patients at risk for contrast nephropathy: decrease in oxidant stress-mediated renal tubular injury.

BACKGROUND: N-Acetylcysteine has been shown to protect against contrast nephropathy, although the mechanisms underlying such an effect are unclear. Surprisingly, studies have shown that post-radiocontrast renal function actually improves in chronic renal failure patients receiving N-acetylcysteine. However, there have been no studies investigating the cause of this improvement. METHODS: In a double-blind, placebo-controlled study, 24 patients (aged 65+/-2 years) suffering from stable mild-to-moderate renal insufficiency and undergoing elective coronary angiography were randomized to receive either placebo or N-acetylcysteine. All received similar hydration. Renal function parameters were assessed 48 h before and 48 h after radiocontrast administration. Urinary 15-isoprostane F2(t), a specific marker of oxidative stress, was measured immediately before and after the procedure. Expression of urinary alpha-glutathione S-transferase protein, a specific proximal tubular injury marker, was assessed after the procedure. RESULTS: Comparing creatinine clearance values before and after angiography, a significant increase was seen in N-acetylcysteine patients (44.7+/-4.2 vs 57.2+/-6.3 ml/min/1.73 m(2); P = 0.02), whereas placebo patients presented no change (46.6+/-5.0 vs 46.9+/-4.3 ml/min/1.73 m(2); P = 0.90). After radiocontrast, urinary 15-isoprostane F2(t) levels in placebo patients increased significantly over baseline values (2.9+/-0.7 vs 10.3+/-2.1 ng/mg creatinine; P = 0.007), whereas urinary 15-isoprostane F2(t) levels in N-acetylcysteine patients remained basically unchanged (3.5+/-0.5 vs 4.1+/-0.9 ng/mg creatinine; P = 0.63). Furthermore, N-acetylcysteine treatment led to lower levels of alpha-glutathione S-transferase than did placebo treatment (0.8+/-0.2 vs 2.4+/-0.7 micro g/g; P = 0.046). CONCLUSIONS: In chronic renal failure patients, the improvement in renal function induced by post-radiocontrast administration of N-acetylcysteine is strongly associated with suppression of oxidant stress-mediated proximal tubular injury.     

N-acetylcysteine attenuates kidney injury in rats subjected to renal ischaemia-reperfusion.

BACKGROUND: The aim of the present study is to examine the effects of N-acetylcysteine (NAC), a thiol-containing anti-oxidant, on renal function and morphology, and biomarkers of oxidative stress, in rats subjected to renal ischaemia-reperfusion (IR). METHODS: Sprague-Dawley rats underwent unilateral nephrectomy and either contralateral renal IR (40 min of renal arterial clamping), or sham manipulation. Treatment groups were: (1) IR-Saline, (2) IR-NAC, (3) Sham-Saline and (4) Sham-NAC. The N-acetylcysteine was administered in a dose of 200 mg/kg intraperitoneally at 24, 12 and 2 h before, and 24, 48 and 72 h after, renal IR. Plasma creatinine was measured on days 1, 3 and 7 after IR, and kidney histology was assessed on day 7. In separate groups of animals we measured renal levels of the anti-oxidant glutathione, markers of systemic oxidative stress (plasma ascorbyl radical, urinary 8-iso-prostaglandin F2alpha), and glomerular filtration rate (GFR) by 51Cr-EDTA clearance, on day 1 after renal IR. RESULTS: Treatment with NAC ameliorated the decline in GFR and reduced hyperkalaemia on day 1 (P<0.05), lowered plasma creatinine levels on days 1 and 3 (P<0.05), and decreased renal interstitial inflammation on day 7 (P<0.05), after renal IR. Kidney glutathione levels decreased significantly in group IR-Saline in response to IR (P<0.05), but were completely repleted in group IR-NAC. Groups with renal IR injury and acute renal failure showed increased plasma ascorbyl radical levels, and elevated urinary 8-iso-prostaglandin F2alpha excretion, compared with sham (P<0.05). N-acetylcysteine treatment reduced plasma ascorbyl concentrations 24 h after renal IR (P<0.05), but had no effect on the rate of urinary 8-iso-prostaglandin F2alpha excretion. CONCLUSIONS: N-acetylcysteine improves kidney function, and reduces renal interstitial inflammation, in rats subjected to renal IR. These effects were associated with increased renal glutathione levels, and decreased plasma ascorbyl concentrations, suggesting that NAC attenuates renal and systemic oxidative stress in this model.     

Oxidative stress and renal injury with intravenous iron in patients with chronic kidney disease

BACKGROUND: Intravenous iron is widely prescribed in patients with chronic kidney disease (CKD) and can cause oxidative stress. The relationship of oxidative stress and renal injury in patients with CKD is unknown. Whether renal injury can occur at a time point when transferrin is incompletely saturated is also unclear. METHODS: We conducted a randomized, open-label, parallel group trial to compare the oxidative stress induced by intravenous administration of 100 mg iron sucrose over 5 minutes and its protection with N-acetylcysteine (NAC) in 20 subjects with stage 3 or 4 CKD. Transferrin saturation was measured with urea polyacrylamide gel electrophoresis, oxidative stress by malondialdehyde (MDA) measurement by high-performance liquid chromatography, and renal injury by enzymuria and proteinuria. Reduced and oxidized glutathione and free radical scavengers as well as urinary monocyte chemoattractant protein-1 were also measured. RESULTS: Parenteral iron increased plasma concentration and urinary excretion rate of MDA, a biomarker of lipid peroxidation, within 15 to 30 minutes of iron sucrose administration. This was accompanied by enzymuria and increase in proteinuria. In contrast, saturation of transferrin was not maximally seen until 3 hours after the end of infusion. Oxidative stress, enzymuria and proteinuria were transient and were completely resolved in 24 hours. NAC reduced acute generation of systemic oxidative stress but failed to abrogate proteinuria or enzymuria. CONCLUSION: Intravenous iron produces oxidative stress that is associated with transient proteinuria and tubular damage. The rapid production of oxidative stress even when transferrin is not completely saturation suggests free iron independent mechanism(s) to be operative in producing oxidative stress and transient renal injury. Long-term implications of these findings need further study.     

Renal tubular acidosis, hypokalemic paralysis, rhabdomyolysis, and acute renal failure--a rare presentation of Chinese herbal nephropathy

We encountered a 66-year-old Chinese man presented with hypokalemic paralysis, rhabdomyolysis and acute renal failure after administration of mixed Chinese herbs. Proximal renal tubular acidosis and selective glucosuria were the main tubular dysfunctions. The renal failure recovered smoothly and rapidly after resuscitation and the tubular function abnormalities regained spontaneously after medicine withdrawal. It should be recognized that renal tubular acidosis with hypokalemic paralysis, rhabdomyolysis and subsequent acute renal failure may develop after taking Chinese mixed herbal medicine.     

Possible cocaine-induced acute renal failure without rhabdomyolysis

Cocaine-induced acute renal failure has been reported in association with rhabdomyolysis. We describe a case of a young African American male who developed acute renal failure, which possibly occurred after inhalation of cocaine without concomitant rhabdomyolysis. His renal function recovered with supportive hydration. The most likely mechanism was intense vasoconstriction. Clinicians need to be mindful of this unique feature of cocaine intoxication.     

Carvedilol, an antihypertensive drug with antioxidant properties, protects against glycerol-induced acute renal failure

BACKGROUND/AIMS: The pathogenesis of glycerol-induced myoglobinuric acute renal failure involves, among other causes, ischaemia, vascular congestion and reactive oxygen metabolites. The aim of this study was to investigate the role of carvedilol, an antihypertensive drug with antioxidative potential, in glycerol-induced acute renal failure in rats. METHODS: Three groups of rats were employed in this study. Group 1 served as control, group 2 was given 50% glycerol (8 ml/kg, i.m.) and group 3 was given glycerol plus carvedilol (3 mg/kg, i.p.). Renal injury was assessed by measuring plasma creatinine, blood urea nitrogen, creatinine and urea clearance. The oxidative stress was measured by renal malondialdehyde levels, reduced glutathione levels and enzymatic activity of catalase, glutathione reductase and superoxide dismutase. RESULTS: Glycerol treatment resulted in marked renal oxidative stress and significantly deranged renal functions. Both of these factors were significantly improved by carvedilol treatment. Carvedilol, by its interaction with Fenton reaction chemistry and radical scavenging activity, protected the kidney against the oxidative stress and resultant renal dysfunction produced by glycerol. CONCLUSION: Based on these results, this study indicates the protective effect of carvedilol in this rhabdomyolysis-mimicking model.     

Acute renal failure in man: pathogenesis in light of new morphological data

The pathogenesis of acute renal failure (ARF) in such common conditions as acute tubular necrosis, acute interstitial nephritis, and primary graft anuria (ischemic transplant ARF) is poorly understood. Animal models may not exactly mimic the situation in man and thus human morphologic studies are of particular importance. Non-replacement of individual sloughed tubular cells and simplification of the brush border and basolateral infoldings of tubular cells are prominent morphologic changes which correlate with the presence of renal failure. It is possible that the initial injury inhibits cell membrane synthesis, thus interfering with proximal tubular sodium reabsorption with resulting activation of the renin angiotensin system and afferent arteriolar vasoconstriction. Tubular backleak, tubular obstruction by casts and debris, and decreased glomerular ultrafiltration coefficient may also play a role. Although poorly studied until now, the renal failure in primary graft anuria may have a completely different pathogenesis from that in acute tubular necrosis and acute interstitial nephritis. Cyclosporine nephrotoxicity is an important component of primary graft anuria, as seen in many transplant centers in the 1980's.