The cancer patient who died because of a medical error at Oakland's Alta Bates Summit Medical Center was killed by a nutritional supplement that a replacement nurse mistakenly put into a catheter meant for delivering medicine to her bloodstream, The Chronicle has learned. The supplement was supposed to be put into a tube that ran into 66-year-old Judith Ming's stomach, said one source close to the investigation. Ming, who suffered from ovarian cancer and had been hospitalized since early July, died early Saturday, soon after the replacement nurse made the mistake. The nurse, a 23-year-old woman from New Orleans, was in a state of shock after realizing what had happened, said a source who spoke on condition of anonymity because patient privacy laws prevent public discussion of many of the case's details.