usually starts down in the lower parts of the body in what's called the "aorta" and migrates upward in humans. but eventually we all get it if we live long enough. and that's sort of a given, that's part of the aging process. who dies from it is the mystery. in 99% of atherosclerosis cases, the patient has high levels of cholesterol built up on the artery walls. jim goldenetz: my father had passed away during bypass surgery in 1986. so i was somewhat aware-- more than most-- that there could be problems with high cholesterol. well, cholesterol is a fatty substance that is in... produced by our bodies or ingested through certain products such as meats. eggs have a lot of cholesterol, for example. so if you were to really describe this molecule called cholesterol, it's a waxy, lipid-type substance that is very similar to fat. the body needs cholesterol to function normally. it is present in all the cell membranes and it helps produce many hormones. but it only takes a small amount of cholesterol to meet the body's needs. hodis: cholesterol is a catchall term of which there are many, many

. >> fortunately for this young man the knife missed his head and his aorta. he had injuries to his liver, his diaphragm, and major blood vessels between the chest and the abdomen. >> reporter: parents waited helplessly to be reunited with their children, frantically trying to find out if they were okay. among them, zack's mom. >> kills you to know that your kids are in there and you can't get them out and you can't do anything about it. it's terrible. >> reporter: the school tucked away in a rural community where some families say they moved to escape urban crime, has no metal detectors. still school officials say they regularly drill for days like this, hoping they never come, and insist students and staff followed the emergency plan, which helped save lives. >> we have to look at it from the standpoint that what we saw happen here today was a very good evidence that the plan does work and the students are safe as safe can be. we haven't lost a life, and i think that's what we have to keep in mind. >> reporter: tonight that 16-year-old suspect is making his

one they're watching carefully because of a stab wound to his kid any, just missing his aorta and his heart. one teen during the arraignment they discussed having been eviscerated. his intestines they were describing in that situation. as for the suspect himself, alex hribal, a soft more here at franklin regional. some students say he was quiet, others says not well known. defense attorneys saying he was a good student. he has no bail set for him. in that discussion between the prosecutor and the defense attorney, they were discussing his ability to stand trial. the prosecutor saying at one point he had said he wanted to die. now, we were able to speak with one of the students here at the high school who was at that time at a bathroom right by that hallway where hribal went down as he went slashing. >> some girl came up to me and said he has a knife, he's stabbing people. that's all i got. nothing else. i went back into the bathroom and i told the girls you got to get out, we've got to go. >> reporter: now, she was at a vigil last night, one of six that happened in murrysville, a town

compromised both the abdominal and the chest cavity, injuring his liver and passing very close to the aorta millimeters. >> that is difficult. this is a young person, presumably a healthy young person. how will this affect your prognosis for him, what you can predict now? >> that is a good question. the fact that he is young and has a healthy heart. he was in a good condition. he actually has a greater chance that someone at a later age he was in a position to tolerate the hemorrhage and the blood loss more than any other patient would, still the injuries were quite severe and he needed aggressive resuscitation both given the case and after in the intensive care unit. >> i'm slur his family is glad they were able to find you and work with upmc trying to take care of this young man. we will be following up and hoping the best comes from you. thank you. >> thank you. >> on the influences former can olympian credit oscar pistorius, third day on the witness stand. rlg lori jane glihloirnlings >> rick: stand. lori jane gliha has the story. >> firing bullets through a closed bathroom door. ask $.

the knife missed his heart and aorta. the resuscitation was critical. he was on life support and this was just as a few minutes ago. the doctors said something extremely interesting. by viewing the wound it was a large knife. we have heard nothing about what was the deadly weapon. >> we just know there were two knives. as far as the suspect goes, we could get more information in half an hour. we know he's a sophomore. what more do you know? >> 16 years old, sophomore. law enforcement is not releasing his name at this point. rather than his name, let's look at his state of mind. the doors had just opened, classes had not begun. this person allegedly walked in with his fellow students, not one but two knives. the crime scene is multiple classroom s and hallways that ae very long. look at that state of mind and that scene and this is something that is critically serious. >> with the deep wounds one would question intention. thank you so much and now to the student that i mentioned, matt is on the phone with me. can you hear me? >> yep, i can hear you. >> w

torr sow compromising the abdominal and the chest cavity, passing close to the aothera, skipping -- aorta skipping the heart by millimetres. >> this is a young person. how does this affect your prognosis. >> that's a good question. the fact that he's young with a healthy heart and he was in good condition. he has a greater chance than someone at a later age. he was in a position to tolerate the haemorrhage and the blood loss more than any other patient would. still, the injuries would be severe. and he needed resuscitation during the case and after - and in the case here. >> i am sure his family is glad they were able to find you and work with upmc. try to take care of this young man. we'll follow up and make sure the best news comes from you. appreciate you being with us. thank you. >> thanks. >> another news. former olympian oscar pistorius faced another gripping day of testimony and sharp challenges from the prosecution at his murder trial. the south african known worldwide as blade runner, accused of shooting and killing his model girlfriend. "america tonight" lori jane gliha is follo

the most seriously wounded, a 17 kwlooeld struck mil meters from his aorta. a brave tackle by assistant principle steve king that ended the ordeal. >> mr. king immobilized him, pinned him down. i jumped on top of him as well and just held down his wrists and arms. >> cuffed by a school security guard, he reportedly told police he wanted to die but so far, no clear motive for either family. >> my first thing, everyone injured today, i hope they recover as quickly as possible. >> they are puzzle pulled. they never saw this coming. family. >> his lawyer told the associate press his client had no history of mental illness and had never been in trouble before. >> he's confused, scared, depressed. you know, within the next few days, we will try to figure out what the heck happened here. >> he has been charge did as an adult with four counts of aattempted homicide and 21 counts of assault. >> officials paraded bravery ofstuents who pulled a fire alarm. others rushed in to the aid. >> there are a number of heroes. students who stayed with their friends and did not le

we've taken this out of the mouse and hooked it up through the aorta to profuse it, to keep it happy.we understand the biology of the pacemaker cells, it's our hope that we can regenerate portions of the conduction system by re-implanting cells that take on this function from those that have degenerated in the patient. more broadly, in terms of the whole heart's electrical system, if we can understand the basis for many forms of lethal cardiac arrhythmias, we can go in and treat those sorts of diseases. cardiovascular disease is the leading cause of mortality in the united states, and sudden cardiac death from arrhythmias is the leading cause of death within the cardiovascular category. it's clearly relevant just in terms of the public health burden that we see from cardiovascular diseases. >> people want to just be able to say some words which explain what happens, but actually what you need is equations and mathematical models and computer simulations, because if you didn't know the basic rules that govern it, you could not have made the model. [ sound of heart beating ] >> it takes

fortunately for this young man, the knife missed his heart and his aorta.rrently in our trauma intensive care unit being -- ongoing resuscitation for his injuries, in critical condition, on life support, and he will require additional surgery in the next several days. >> what is his prognosis? >> he is in critical condition, but we are hopeful he will make it through this. >> what is his name? >> i cannot provide that at this time. he is 17 years old. i understand he was a senior in high school. i don't have direct information on that. we are providing support with social workers and other appropriate support to the teenagers at this time. >> -- the one you just described, considered the most serious -- >> yes, he's the most seriously injured patient i'm aware of in the upmc system. >> can you give us a little more information about what the next few days hold for him? >> the next several days will include ongoing treatment for bleeding and treating blood clotting disorders that occur with major trauma in intensive care unit with transfusion of blood produc

fortunately for this young man, the knife missed his heart, and his aorta.re unit, with ongoing resuscitation for his injuries, in critical condition, on life support. and he will require additional surgery in the next several days. >> what is his prognosis? >> he is in critical condition, but we're very hopeful he will make it through this. >> what's his name? >> i cannot provide that at this time. >> [ inaudible ]? >> he is 17 years old. i understand he was in the senior high school. >> how are they handling this psychologically? how is their mood? >> i don't have direct information on that. we are providing support with social workers and other appropriate support to the teenagers at this time. >> the one you just described -- [ inaudible ]? >> he's the most seriously injured patient that i'm aware of in the upmc system. >> can you give us a little bit more information about what the next few days hold for him? >> the next several days will include ongoing treatment for bleeding, and treating blood clotting disorders that occur with major trauma in the in