Response by Pasupathy et al to Letters Regarding Article, "early Use of N-acetylcysteine (NAC) with Nitrate Therapy in Patients Undergoing Primary Percutaneous Coronary Intervention for ST-Segment Elevation Myocardial Infarction Reduces Myocardial Infarct Size (The NACIAM Trial [N-Acetylcysteine in Acute Myocardial Infarction])"