***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: AIM OF THE STUDY The frequency of acute renal failure ( ARF ) after preservation and kidney transplantation is rather high . The etiology of an ARF is an interaction of multiple mechanisms as donor conditions , explantation procedure , duration of ischemia and reperfusion injury . Different experiments demonstrated , that the damage produced by reperfusion can be prevented by the scavenger of free radicals , the enzyme superoxide dismutase ( SOD ) . PATIENTS AND METHODS After a double blind study , using consecutive intraarterial bovine SOD ( n = 100 ) in kidney transplantation , showing a trend in favour to the SOD treated group , especially when long-time stored kidneys ( > 30 h ) had been grafted , a second study was design ed to evaluate the efficiency of intravenous recombinant human SOD in the protection from ARF . This study ( n = 180 ) was split into two different trials , double blind and r and omized in itself : ( A ) grafts with cold ischemia time lower or equal 30 hrs . , ( B ) cold ischemia more than 30 hrs . All grafts were preserved with Euro-collins . The study substances were either placebo or 200 mg rh-SOD ( Grünenthal GmbH , FRG ) , given 10 - 2 minutes prior reperfusion intravenously . Parameters causing an ARF were equal and well comparable in both groups . RESULTS Concerning early graft function there was no difference in study A between placebo and rh-SOD group . In study B the average and median of the day creatinine dropped the first time without interference of hemodialysis , showed a trend in favour to the rh-SOD group . If placebo was given only 19 % of the grafts gained function within the first week , when rh-SOD was applied 47 % functioned in the first week . The lack of significant benefit from SOD treatment could be explained by the dependency of the proportion of the total injury caused by reperfusion compared with the proportion result ing from ischemic injury per se . The rh-SOD group showed a better 3 years graft survival rate ( + 16 % ) . CONCLUSIONS It seems rh-SOD is able to augment the early graft function and is helpful to reduce the ARF frequency when long-time stored cadaveric kidneys have to be transplanted . These promising results encourage us to continue the study in protocol B to get greater numbers and definitive results BACKGROUND There is conflicting evidence on the benefits of foods rich in vitamin E ( alpha-tocopherol ) , n-3 polyunsaturated fatty acids ( PUFA ) , and their pharmacological substitutes . We investigated the effects of these substances as supplements in patients who had myocardial infa rct ion . METHODS From October , 1993 , to September , 1995 , 11,324 patients surviving recent ( < or = 3 months ) myocardial infa rct ion were r and omly assigned supplements of n-3 PUFA ( 1 g daily , n=2836 ) , vitamin E ( 300 mg daily , n=2830 ) , both ( n=2830 ) , or none ( control , n=2828 ) for 3.5 years . The primary combined efficacy endpoint was death , non-fatal myocardial infa rct ion , and stroke . Intention-to-treat analyses were done according to a factorial design ( two-way ) and by treatment group ( four-way ) . FINDINGS Treatment with n-3 PUFA , but not vitamin E , significantly lowered the risk of the primary endpoint ( relative-risk decrease 10 % [ 95 % CI 1 - 18 ] by two-way analysis , 15 % [ 2 - 26 ] by four-way analysis ) . Benefit was attributable to a decrease in the risk of death ( 14 % [ 3 - 24 ] two-way , 20 % [ 6 - 33 ] four-way ) and cardiovascular death ( 17 % [ 3 - 29 ] two-way , 30 % [ 13 - 44 ] four-way ) . The effect of the combined treatment was similar to that for n-3 PUFA for the primary endpoint ( 14 % [ 1 - 26 ] ) and for fatal events ( 20 % [ 5 - 33 ] ) . INTERPRETATION Dietary supplementation with n-3 PUFA led to a clinical ly important and statistically significant benefit . Vitamin E had no benefit . Its effects on fatal cardiovascular events require further exploration The antioxidant effect of dietary beta-carotene supplementation on the peroxidation potential of plasma was investigated in a r and omized double-blind , placebo-controlled study . Twelve healthy women ( 62 - 80 y ) supplemented their usual daily diet with 90 mg of beta-carotene ( n = 6 ) or placebo ( n = 6 ) capsules for 3 wk . Plasma concentrations of beta-carotene , alpha- and gamma-tocopherol , ascorbate , urate , bilirubin and in vitro production of phosphatidylcholine hydroperoxides ( PC-OOH ) and utilization of plasma antioxidants in the presence of 50 mmol/L 2,2'-azobis ( 2-aminopropane ) hydrochloride ( AAPH ) , a free radical generator , at 37 degrees C were measured before and after dietary treatment . Plasma beta-carotene increased from 0.76 + /- 0.16 to 6.45 + /- 1.16 micromol/L ( P < 0.05 ) in supplemented but not placebo-treated subjects . The plasma concentrations of other antioxidants did not change significantly in either group . beta-Carotene supplementation did not affect basal levels of plasma PC-OOH as measured by HPLC post-column chemiluminescence but did affect AAPH-induced production of PC-OOH . Before supplementation , the induction period of plasma PC-OOH production was 2.4 + /- 0.4 h , with levels reaching 5.39 + /- 1.50 micromol/L after 6 h of incubation . After supplementation , the induction period increased significantly to 4.2 + /- 0.4 h ( P < 0.01 ) , with a lower PC-OOH production of 2.16 + /- 0.90 micromol/L after 6 h ( P < 0.05 ) . In this system , plasma ascorbate concentrations were depleted first , followed by loss of bilirubin and alpha-tocopherol and then by the sequential loss of gamma-tocopherol , urate and beta-carotene . These results indicate that beta-carotene supplementation increases the plasma antioxidant capacity of older women Background — Patients with end-stage renal failure have increased oxidative stress and show elevated cardiovascular mortality . Whether increased cardiovascular events can be prevented by the administration of antioxidants is unknown . Methods and Results —We evaluated the effects of acetylcysteine , a thiol-containing antioxidant , on cardiovascular events in patients undergoing hemodialysis . A prospect i ve , r and omized , placebo-controlled trial was conducted between October 1 , 1999 , and September 30 , 2001 , in 134 patients ( 76 male and 58 female ) with a mean age of 62±16 years ( mean±SD ) who had been undergoing maintenance hemodialysis for a minimum of 3 months 3 times weekly in an ambulatory center . Median ( range ) follow-up was 14.5 ( 1 to 24 ) months . Patients were r and omly assigned either to receive acetylcysteine ( 600 mg BID ) or placebo . The primary end point was a composite variable consisting of cardiac events including fatal and nonfatal myocardial infa rct ion , cardiovascular disease death , need for coronary angioplasty or coronary bypass surgery , ischemic stroke , peripheral vascular disease with amputation , or need for angioplasty . Secondary end points included each of the component outcomes , total mortality , and cardiovascular mortality . A total of 18 ( 28 % ) of the 64 hemodialysis patients assigned to acetylcysteine group and 33 ( 47 % ) of the 70 hemodialysis patients assigned to control group had a primary end point ( relative risk , 0.60 [ 95 % CI , 0.38 to 0.95 ] , P = 0.03 ) . No significant differences in secondary end points or total mortality were detected . Conclusions —In hemodialysis patients , treatment with acetylcysteine ( 600 mg BID ) reduces composite cardiovascular end points Patients with chronic renal impairment ( CRI ) are at greatly increased risk for premature vascular disease ; however , little is known about its evolution . This paper describes a cohort of patients with CRI and reports study design , baseline demographic and biochemical data , and comparisons with two contemporaneous age- and sex-matched control groups , one with established coronary artery disease and the other without overt vascular disease . Among 369 individuals ( median age , 63 years ; range , 18 to 88 years ; 67 % men ) with CRI , 34 % had a history of vascular disease and 21 % had electrocardiographic left ventricular hypertrophy ( LVH ) . Even in those with mild renal impairment ( serum creatinine < 2.1 mg/dL ) , approximately one third had vascular disease and 12 % had LVH . A history of hypertension was present in 76 % of the CRI group , but as compared with controls , systolic and diastolic blood pressures were not elevated . Low-density lipoprotein ( LDL ) cholesterol concentration also was not elevated , but CRI was associated with elevated serum triglyceride and plasma homocysteine levels and reduced high-density lipoprotein ( HDL ) cholesterol , hemoglobin , and serum albumin concentrations . Across the spectrum of CRI , more severe renal dysfunction was associated with lower levels of diastolic blood pressure , LDL and HDL cholesterol , albumin , and hemoglobin , but increased levels of plasma homocysteine . This cross-sectional analysis shows that vascular disease is common in individuals with mild CRI attending a nephrology program and also suggests trends in the levels of a number of potential vascular risk factors with respect to severity of renal dysfunction . These results will be further quantified in a prospect i ve biennial follow-up Background . The bioflavonoids quercetin and curcumin are renoprotective natural antioxidants . We wished to examine their effects on early graft function ( EF ) . Methods . Between September 2002 and August 2004 , 43 dialysis dependent cadaveric kidney recipients were enrolled into a study using Oxy-Q which contains 480 mg of curcumin and 20 mg of quercetin , started after surgery and taken for 1 month . They were r and omized into three groups : control ( placebo ) , low dose ( one capsule , one placebo ) and high dose ( two capsules ) . Delayed graft function ( DGF ) was defined as first week dialysis need and slow function ( SGF ) as Cr > 2.5 mg/dl by day 10 . Category variables were compared by chi squared and continuous variables by Kruskal-Wallis . Results . There were four withdrawals : one by patient choice and three for urine leak . The control group had 2/14 patients with DGF vs. none in either treatment group . Incidence of EF was control 43 % , low dose 71 % and high dose 93 % ( P=0.013 ) . Serum creatinine was significantly lower at 2 days ( control 7.6±2.1 , low 5.4±0.6 , high 3.96±.35 P=0.0001 ) and 30 days ( control 1.82±.16 , low 1.65±.09 , high 1.33 ±.1 , P=0.03 ) . Acute rejection incidence within 6 months was control 14.3 % , low dose 14.3 % and high dose 0 % . Tremor was detected in 13 % of high dose patients vs. 46 % of others . Urinary HO-1 was higher in bioflavonoid groups . Conclusion . Bioflavonoid therapy improved early graft function . Acute rejection and neurotoxicity were lowest in the high dose group . These bioflavonoids improve early outcomes in cadaveric renal transplantation , possibly through HO-1 induction BACKGROUND Renal failure after lower torso ischemia is a serious problem , partly caused by hypotension and indirect reperfusion injury . This injury is partly due to the formation of oxygen free radicals by activated neutrophils . This injury results in albuminuria and renal function impairment . There are indications that free radical damage in indirect reperfusion injury can be diminished by administering extra antioxidants before and during reperfusion . METHODS In this prospect i ve r and omised study we have looked at the influence of a multi-antioxidant supplementation on renal function in patients undergoing an elective open infrarenal abdominal aneurysm repair . The patients received either  st and ard treatment ( n=22 ) or st and ard treatment with additional antioxidants perioperatively ( Allopurinol , vitamin E and C , N-acetylcysteine and mannitol ) . For renal function we have looked at the albumin/creatinine ratio in ur 
    Output:
    
Although antioxidant therapy does not reduce the risk of cardiovascular and all-cause death or major cardiovascular events in people with CKD , it is possible that some benefit may be present , particularly in those on dialysis .
Current evidence suggests that antioxidant therapy in predialysis CKD patients may prevent progression to ESKD ; this finding was however based on a very small number of events .