***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: Background : Pharmacokinetic data suggests that the intravenous form of n‐acetylcysteine ( NAC ) may be more effective than the oral formulation in preventing contrast induced nephropathy ( CIN ) . NAC owing to its anti‐oxidant properties might be beneficial for patients with acute coronary syndromes ( ACS ) who are at increased risk for CIN . The aim of this prospect i ve r and omized , single‐center , double‐blind , placebo controlled trial ( NCT00939913 ) was to assess the effect of high‐dose intravenous NAC on CIN in ACS patients undergoing coronary angiography and /or percutaneous coronary intervention ( PCI ) . Methods : We r and omized 398 ACS patients scheduled for diagnostic angiography ± PCI to an intravenous regimen of high‐dose NAC ( 1,200 mg bolus followed by 200 mg/hr for 24 hr ; n = 206 ) or placebo ( n = 192 ) . The primary end‐point was incidence of CIN defined as an increase in serum creatinine concentration ≥25 % above the baseline level within 72 hr of the administration of intravenous contrast . Results : There was no difference found for the primary end point with CIN in 16 % of the NAC group and in 13 % of the placebo group ( p = 0.40 ) . Change in serum cystatin‐C , a sensitive marker for renal function , was 0.046 ± 0.204 in the NAC group and 0.002 ± 0.260 in the control group ( p = 0.07 ) . Conclusion : In ACS patients undergoing angiography ± PCI , high‐dose intravenous NAC failed to reduce the incidence of CIN . © 2011 Wiley Periodicals , To determine the incidence of contrast-induced nephropathy ( CIN ) and to assess the effectiveness of ascorbic acid in the prevention of CIN after coronary angiography in patients with chronic renal impairment . CIN is the third most common cause of hospital-acquired renal failure . It is well documented that periprocedural hydration is effective in the prevention of CIN . Little data exist on the effectiveness of ascorbic acid , a vitamin with antioxidative action . Patients with stable serum creatinine level > 107 μmol/L ( n = 81 ) undergoing coronary angiography were r and omized to receive either ascorbic acid ( N = 40 ) or placebo ( N = 41 ) before the procedure . All patients received intravenous volume expansion with normal saline before the procedure . CIN was defined as an increase of serum creatinine level > 25 % from baseline measured 3 to 4 days after the procedure . CIN occurred totally in 5/81 patients ( 6.2 % ) ; in two patients ( 3 % ) in the ascorbic acid group and in three patients ( 7.3 % ) in the placebo group ( P = 0.512 ) . Postprocedural worsening of renal function ( postprocedural increase of serum creatinine level ) was present in 10/81 patients ( 12.3 % ) in the ascorbic acid group and in 19/81 patients ( 23.4 % ) in the placebo group ( P = 0.038 ) . No patient required dialysis treatment . We found no statistically significant impact of ascorbic acid on the incidence of CIN in patients with chronic renal impairment undergoing coronary arteriography or angioplasty .  Ascorbic acid may still have some protective role in CIN reflected in lower incidence of worsening of renal function in the treated group OBJECTIVES Prophylactic acetylcysteine along with hydration seems to be better than hydration alone in preventing the reduction in renal function induced by a contrast dye . BACKGROUND Contrast media can lead to acute renal failure that may occasionally require hemodialysis . METHODS One hundred eighty-three consecutive patients with impairment of renal function , undergoing coronary and /or peripheral angiography and /or angioplasty , were r and omly assigned to receive 0.45 % saline intravenously and acetylcysteine ( 600 mg orally twice daily ; group A , n = 92 ) or 0.45 % saline intravenously alone ( group B , n = 91 ) before and after nonionic , low-osmolality contrast dye administration . RESULTS The baseline serum creatinine concentrations were similar ( 1.5 + /- 0.4 mg/dl in group A vs. 1.5 + /- 0.4 mg/dl in group B ; p = 0.37 ) . An increase of > or = 25 % in the baseline creatinine level 48 h after the procedure occurred in 6 ( 6.5 % ) of 92 patients in group A and in 10 ( 11 % ) of 91 patients in group B ( p = 0.22 ) . In the subgroup with a low ( < 140 ml ) contrast dose , renal function deterioration occurred in 5 ( 8.5 % ) of 60 patients in group B and in 0 of 60 patients in group A ( p = 0.02 ; odds ratio [ OR ] 0.44 , 95 % confidence interval [ CI ] 0.35 to 0.54 ) . In the subgroup with a high contrast dose , no difference was found ( 5/31 vs. 6/32 patients , p = 0.78 ) . By multivariate analysis , the amount of contrast agent , but not the treatment strategy , was a predictor of the occurrence of contrast dye-associated nephrotoxicity ( OR 2.58 , 95 % CI 1.1 to 4.9 ; p = 0.035 ) . CONCLUSIONS In patients with reduced renal function undergoing angiography and /or angioplasty , the amount of contrast agent , but not the administration of prophylactic acetylcysteine , was a predictor of renal function deterioration .  Prophylactic acetylcysteine might provide better protection than hydration alone , only when a small volume of contrast agent is used OBJECTIVES The aim of this r and omized , single-blind , controlled trial was to assess N-acetylcysteine effects on contrast-induced nephropathy and reperfusion injury in ST-segment elevation myocardial infa rct ion patients undergoing primary angioplasty with moderate contrast volumes . BACKGROUND High-dose N-acetylcysteine reduced the incidence of contrast-induced nephropathy in patients with high contrast volumes and reduced reperfusion injury in animal trials . METHODS Patients undergoing primary angioplasty were r and omized to either high-dose N-acetylcysteine ( 2 x 1,200 mg/day for 48 h ; n = 126 ) or placebo plus optimal hydration ( n = 125 ) . The 2 primary end points were : 1 ) the occurrence of > 25 % increase in serum creatinine level < 72 h after r and omization ; and 2 ) a reduction in reperfusion injury measured as myocardial salvage index by magnetic resonance imaging . RESULTS The median volume of an iso-osmolar contrast agent during angiography was 180 ml ( interquartile range [ IQR ] 140 to 230 ml ) in the N-acetylcysteine and 160 ml ( IQR 120 to 220 ml ) in the placebo group ( p = 0.20 ) . The primary end point contrast-induced nephropathy occurred in 14 % of the N-acetylcysteine group and in 20 % of the placebo group ( p = 0.28 ) . The myocardial salvage index was also not different between both treatment groups ( 43.5 ; IQR 25.4 to 71.9 vs. 51.5 ; IQR 29.5 to 75.3 ; p = 0.36 ) . Activated oxygen protein products and oxidized low-density lipoprotein as markers for oxidative stress were reduced by as much as 20 % in the N-acetylcysteine group ( p < 0.05 ) , whereas no change was evident in the placebo group . CONCLUSIONS High-dose intravenous N-acetylcysteine reduces oxidative stress . However , it does not provide an additional clinical benefit to placebo with respect to CIN and myocardial reperfusion injury in nonselected patients undergoing angioplasty with moderate doses of contrast medium and optimal hydration . ( Myocardial Salvage and Contrast Dye Induced Nephropathy Reduction by N-Acetylcysteine [ LIPSIA-N-ACC ] ; NCT00463749 ) OBJECTIVE To evaluate the use of N-acetylcysteine ( NAC ) , a potent antioxidant , to prevent contrast-induced nephropathy ( CIN ) . METHODS We prospect ively studied 209 patients ( 106 in the NAC group and 103 in the control group ) who received contrast-enhanced computed tomography ( CECT ) in the emergency department ( ED ) . The NAC group received intravenous NAC ( 600 mg ) before CECT imaging to prevent CIN . Both the NAC and control groups were treated using a st and ardized hydration strategy , where clinical ly feasible . RESULTS The patients ' mean age was 79.6±9.8 years . The prevalence of hypertension , diabetes , and chronic kidney disease ( CKD ) were 63.2 % , 27.3 % , and 21.5 % , respectively . The baseline clinical characteristics were similar between the two groups except for their body weight ( p=0.011 ) , amount of contrast material administered ( p=0.049 ) and prevalence of CKD ( p=0.002 ) . The incidence of CIN was 7.5 % in the NAC group and 14.6 % in the control group . The adjusted odds ratio was 0.305 ( 95 % confidence interval : 0.097 to 0.960 , p=0.042 ) . All-cause mortality was 7.5 % in the NAC group and 12.6 % in the control group , which was not significantly different . Temporary hemodialysis was required in 0 % of subjects in the NAC group and 1.0 % in the control group , which was not a statistically significant difference . CONCLUSION A single dose of NAC before CECT imaging can prevent CIN in an ED setting . However , it does not improve the mortality rate or the need for dialysis BACKGROUND Contrast-induced nephropathy ( CIN ) is one of the important complications of coronary angiography ( CAG ) and percutaneous coronary intervention ( PCI ) , especially in patients with chronic kidney disease ( CKD ) . Prophylactic administration of N-acetylcysteine ( NAC ) and aminophylline has been reported to be effective in some trials , but the results still remain controversial . We investigated the efficacy of NAC or aminophylline in preventing CIN . METHODS AND RESULTS Forty-five consecutive patients undergoing CAG and /or PCI were r and omly assigned to receive hydration and NAC ( 704 mg orally twice daily ; NAC group , n=15 ) , hydration and aminophylline ( 250 mg intraveneously 30 min before CAG and /or PCI ; aminophylline group , n=15 ) , or hydration alone ( control group , n=15 ) . We compared serum creatinine ( SCr ) , creatinine clearance ( Ccr ) , blood beta-2 microglobulin , and urinary beta-2 microglobulin levels at baseline and 48h after CAG and /or PCI . In the NAC group , SCr decreased from 1.00 + or - 0.36 to 0.67 + or - 0.16 mg/dl ( p<0.01 ) , and Ccr significantly increased from 62.4 + or - 15.6 to 80.4 + or - 8.39 ml/min ( p<0.01 ) . In the aminophylline group , SCr and Ccr were unchanged . In the control group , SCr significantly increased from 0.94 + or - 0.21 to 1.28 + or - 0.21 mg/dl ( p<0.01 ) , and Ccr significantly decreased from 63.7 + or - 16.1 to 46.1 + or - 10.6 ml/min ( p<0.01 ) after CAG and /or PCI . In the NAC group , mean blood beta-2 microglobulin significantly decreased from 2.38 + or - 0.58 to 1.71 + or - 0.38 mg/dl ( p<0.01 ) , and in the aminophylline group , mean urinary beta-2 microglobulin concentration significantly decreased from 337 + or - 31.0 to 239 + or - 34 microg/ml ( p<0.01 ) . CONCLUSIONS These results suggest that both prophylactic NAC and aminophylline administration are effective in preventing CIN , but not with hydration alone . It appears that the two compounds work in different ways against CIN The nephroprotective role of N-acetylcysteine ( NAC ) against contrast-induced neph 
    Output:
    
N-acetylcysteine Plus IV Saline Versus IV Saline N-acetylcysteine is a direct scavenger of free radicals and improves blood flow through nitric oxidemediated pathways , which results in vasodilatation .
As a result , both the antioxidant and vasodilatory properties of N-acetylcysteine are believed to protect against CIN .