tonight, a surprise announcement from congresswoman gabby giffords. >> i will step down this week. >> what's behind her sudden decision? the amazing race. the fight for the republican nomination, now a free for all after newt gingrich's stunning victory. remembering joe paterno. tonight, the life of a beloved coach, his legendary career ended suddenly by scandal. hidden danger. important health news about a vital test, new guidelines for millions of women. and, life saver. with time running out, a nurse's extraordinary gift to the patient in her care. captions paid for by nbc-universal television

good evening. a surprising announcement today from congresswoman gabrielle giffords, whose remarkable comeback became a source of inspiration in the midst of a horrible tragedy. it was a year ago this month giffords was shot through the head in an assassination attempt that killed six people outside a tucson, arizona, grocery store. she had to learn to speak and walk all over again. but today, acknowledging that her recovery is not complete, gabby giffords announced she's resigning from congress in a poignant video thank you to her supporters, she said she was getting better, but that she needed more time to heal. our capitol hill correspondent kelly o'donnell is with us now with more on giffords' announcement and the reaction to it. kelly, good evening. >> reporter: good evening, lester. congresswoman giffords will be back in washington tuesday night to attend the state of the union. it will be one of her final acts

in public office. the president tonight called her her decision selfless and said it was made in the best interests of the people of arizona and the congresswoman made her announcement with a sort of campaign style video. >> arizona is my home, always will be. >> reporter: using music and images, giffords' video pays tribute to her home state and consti >> i don't remember much from that horrible day, but i will never forget the trust you placed in me to be your voice. >> reporter: it was one year and two weeks ago that a storm of bullets shattered giffords' congress on your corner event in tucson. giffords was shot in the head and gravely wounded. six people were killed, and a dozen injured. the accused gunman jared loughner remains in custody,

declared not mentally fit to stand trial. >> i'm getting better. >> reporter: along with husband retired astronaut mark kelly, giffords has made only a handful of public appearances. stunning how colleagues, while returning to vote last august, and leading the pledge of allegiance at a vigil to mark the shooting anniversary. she ends her public career after five years in congress. >> so to do what is best for arizona, i will step down this week. >> reporter: today, house speaker john boehner says he salutes giffords for the courage and perseverance she has shown in the face of tragedy. democratic leader nancy pelosi calls her a true bright star. >> i will return and we will work together. >> reporter: arizona's governor is expected to announce a date for a special election so voters can choose gabby giffords' successor who will fill out the

rest of her term, which runs the rest of this year. lester? >> kelly o'donnell on capitol hill tonight. kelly, thank you. to presidential politics now and the stunning victory by newt gingrich in the south carolina primary. gingrich won by a whopping 12 points over mitt romney, blowing the race for the republican nomination wide open as the candidates head for florida. and that's where we find nbc's peter alexander tonight in orman beach. good evening to you. >> reporter: lester, good evening to you. it is looking more and more like a two-man race here between mitt romney and newt gingrich. after his dramatic win in south carolina yesterday, today gingrich said he's already raised a million dollars in campaign donations and is aiming to raise a million more for what he describes as the knockout punch. after his triumphant come from behind win, newt gingrich delivered a populous message, insisting his victory was a vindication. >> we proved here in south carolina that people of power with the right ideas beats big

money and with your help, we'll prove it again in florida. >> reporter: while the resounding defeat upended mitt romney's position as the presumed front-runner, he said he's prepared for the long haul and without referring to gingrich by name, argued a washington insider can't beat president obama. >> our party can't be led to victory by someone who also has never owned a business and never run a state. >> reporter: despite his third place finish, rick santorum says he feels no pressure to drop out. >> i think people realize that it is mitt romney is now no longer the inevitable. >> reporter: after romney's wavering answers about when hes would release his tax returns -- >> maybe. you know, i don't know how many years i'll release. >> reporter: romney today committed to releasing both his 2010 returns and an estimate for his 2011 returns tuesday. >> i think we just made a mistake in holding off as long as we did. it was a distraction. we want to get back to the real issues in the campaign. >> reporter: gingrich says he'll behind to focus on romney's record as a venture capitalist.

>> questions about the character, the judgment, the record of a presidential candidate is not an attack on business. that's silly. >> reporter: today, gingrich was on the attack again, defending his role with the federal mortgage housing agency freddie mac. >> wait a second, david. david, you know better than that. i was not a lobbyist. i was never a lobbyist. i never did any lobbying. don't try to mess these things up. the fact is i wasn't an adviser strategically. >> reporter: and chris christie, a romney supporter, bluntly criticized gingrich's career in politics. >> i think he has embarrassed the party over time, whether he'll do it again in the future, i don't know. but governor romney never has. >> reporter: and the battle here in florida is already well under way. nearly 200,000 people have already cast their ballots, lester, either by absentee or early voting in this state. >> peter alexander in florida, thanks. chuck todd is nbc news political director and chief white house correspondent. he joins us now from tampa, florida, site of tomorrow night's nbc news presidential debate.

you see the set there behind h m him. chuck, let me ask you how the debates may have hurt romney in south carolina and how you expect him to change, perhaps, when he goes back on the podium tomorrow. >> well, it is interesting we do sort of -- mitt romney telegrafd he'll get more aggressive against speaker gingrich. speaker gingrich has shown his ability to be aggressive with the moderate, a little bit with his opponents. it will be interesting to watch romney do this. four years ago, almost in this exact same period in the presidential race, he was feeling the pressure from huckabee and mccain, romney went on the attack and his numbers went down even lower. in fact, at the florida debates then he was very aggressive and it didn't help him. he struggles walking that line of going on the attack and at the same time without turning off voters and newt gingrich is somebody that knows he lives for these moments. he knows how to respond and sort of get under mitt romney's skin in a way that we haven't seen in a while, lester. >> a couple of weeks ago, a lot of folks thought romney was cruising to victory in south

carolina. he was buying up ad time in florida. explain the landscape in florida now as this campaign essentially gets reset. >> reporter: it is and they have always viewed it as their second firewall. new hampshire was one. this was the second one. but it is a close primary, meaning only registered republicans who voted, it is a lot more conservative than new hampshire, only slightly more moderate than south carolina. it is a big state. the question is, does gingrich have the resources to take advantage of his momentum? that's an open question, lester. >> chuck todd. chuck, thank you very much. brian williams moderates the republican candidates debate from florida tomorrow night at 9:00, 8:00 central here on nbc. we learned today that one of the most legendary sports figures of the last half century has died. penn state football coach joe paterno whose legacy was forever stained by the scandal that cost him his job. he passed away early this morning after a short battle with lung cancer. and nbc's michelle franzen has reaction on the penn state campus tonight.

michelle, good evening. >> reporter: >> good evening, lester. here outside the stadium, a steady stream of people have been coming to pay tribute all day, laying flowers and candles at the base of joe paterno's statue. this place and the man many say symbolizes the heart and soul of penn state. along with grief throughout the day, there was also a strong showing of pride for this legendary football coach. >> joepa was our father, like everyone. he brought penn state together, really. so it was hard seeing him and terrible this has happened. >> joe has done a tremendous amount for this university and i just hope that we can all remember him for the good that he did and not what happened this past november. >> reporter: earlier today the paterno family released this statement following his death saying, quote, he died as he lived. he fought hard until the end, stayed positive, thought only of others and constantly reminded everyone of how blessed his life had been.

back here at the stadium, people continue to come here tonight in quiet and somber reflection, a vigil is also planned back on campus in this community waiting for word from the family on funeral and memorial plans. lester? >> michelle, and joe paterno coached the nittany lions every season since lyndon johnson was in the white house, nearly half a century, pacing the sidelines at penn state. a look back tonight from nbc's ron allen. >> reporter: joe paterno was one of the greatest figures ever in college sports. 46 years as head coach at penn state, 409 victories, the most of the division one school. from his idealistic early days, paterno had implemented what he called a grand experiment, to graduate more players while maintaining success on the field. most recently his teams consistently ranked monday the best in the big ten for graduating players. the coach took the nittany lions to 37 bowl games, and two national championships, hundreds

of the players he coached went on to the nfl. penn state became known as happy valley. >> people ask me why i stayed here so long, and, you know what, look around. look around. i stayed here because i love you all! >> reporter: but last year, everything changed. in his final days, paterno battled lung cancer, his spirit and legacy battered by the child sexual abuse scandal centered around his long time assistant jerry sandusky. >> i had never had to deal with something like that. and i didn't feel adequate. >> reporter: penn state fired paterno last november. he had been widely criticized for not taking more responsibility or confronting sandusky. after his dismissal, paterno tried to stay positive. >> i've had a wonderful experience here at penn state. i don't want to walk away from this thing bitter. >> reporter: joseph paterno was born december 21st, 1926 in

brooklyn, new york, a depression era child of italian immigrants. he graduated from brown university, served a year in the u.s. army as world war ii ended, and then went to coach at penn state as an assistant where he stayed for 61 years. beyond all the football glory, paterno also gave millions of dollars to penn state for academics. a legendary coach, in the end tainted by scandal, who leaves a very complicated legacy behind. ron allen, nbc news, new york. in italy tonight, new questions are being raised about whether there were more people on board that capsized cruise ship than the official manifest shows. this as the official death toll grew yet again today. nbc's duncan golestani is on the island of giglio with the latest on the search for victims. >> reporter: all week families of the missing have been waiting for news of their loved ones, including a missing american couple. this is not what they had hoped for. the 13th victim of the costa

concordia is brought ashore. this man says divers found the body of a woman on deck seven. like yesterday's victims, she too was wearing her life vest and is believed to have been a passenger. families gathered on the island now have an anxious few days as the woman is identified. because of the time spent in the water, five bodies have still not yet been named, a task even more complicated because authorities now think the cruise liner had unregistered passengers on board. while the search for the missing continues, pressure grows to speed up the salvage operation. the island's residents concerned there isn't a second disaster, a environmental one. the salvage team says it could take seven weeks to extract the half a million gallons of fuel. this fisherman says they fear that this discharge from the tank is polluting the sea. the operation could start as early as tomorrow. it can't come soon enough for the residents of this small,

quiet island. duncan golestani, nbc news, giglio, italy. when "nbc nightly news" continues, a hidden danger for millions of women. important new guidelines about a vital test to find it. and later, he searched far and wide for a donor to save his life. turns out she was right beside him all along. i've been so looking forward to this. when my asthma symptoms returned, my doctor prescribed dulera to help prevent them. [ male announcer ] dulera is for patients 12 and older whose asthma is not well controlled on a long-term asthma control medicine, like an inhaled corticosteroid. dulera will not replace a rescue inhaler for sudden symptoms. dulera helps significantly improve lung function. this was shown over a 6 month clinical study. dulera contains formoterol, which increases the risk of death from asthma problems and may increase the risk of hospitalization in children and adolescents. dulera is not for people whose asthma is well controlled with a long-term asthma control medicine, like an inhaled corticosteroid. once your asthma is well controlled

your doctor will decide if you can stop dulera and prescribe a different asthma control medicine, like an inhaled corticosteroid. do not take dulera more than prescribed. see your doctor if your asthma does not improve or gets worse. ask your doctor if dulera can help you breathe easier. ♪ than these gas relievers. these you take after food gives you gas, you take beano before, so you don't get gas. and if you don't get gas, maybe you don't need these. take beano before and there'll be no gas. [ roger ] tell me you have good insurance. yup, i've got... [ dennis ] ...allstate. really? i was afraid you'd have some cut-rate policy. [ kyle ] nope, i've got... [ dennis ] ...the allstate value plan. it's their most affordable car insurance -- and you still get an allstate agent. i too have... [ dennis ] ...allstate. [ roger ] same agent and everything. [ kyle ] it's like we're connected. no we're not. yeah, we are. no...we're not. ♪ the allstate value plan.

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doctors are sounding the alarm about osteoporosis, urging more older will to be screened. at the same time, there are concerns the tests are done too often. at least for some women. we get our report from our chief science correspondent robert bazell. >> reporter: a bone density test usually done on older women measures the risk of getting osteoporosis and dangerous fractures that often follow. but women with healthy bones do not need to be tested as often as they have been because few will actually develop osteoporosis. >> it is unnecessary to keep screening every two or three years. >> reporter: dr. ethel cyrus, an osteoporosis specialist, agrees with the study's results, but emphasizes the importance of getting an initial test at age 65. >> medicare says when you're 65, if you haven't had a bone density, you should have one. and yet only about 20% of general medicare recipients do the test. it should be probably 95%. >> reporter: and what about younger women? well, the bone starts to thin after menopause, usually around

age 50. experts say it is not worth the money to test most women at that age, because there is not much risk. >> i think the issue has to do with resources, health care resources and how we spend our money. >> reporter: she says a woman at age 50 should get the test, because she had a fracture since age 45. a parent who fractured a hip, takes certain medications, or has certain diseases that cause bone thinning. she reiterates that all women should get the test at age 65. the latest study finds that if their bones are strong, they don't need another test for 15 years. >> be grateful you had good genes, continue to do the good things everybody should do for bone health, get enough calcium, enough vitamin d, be physically acti active. as you grow older, be aware if something changes, you need to revisit the whole question. >> reporter: if the test finds thinning bones, she and many experts say the woman needs treatment with medication and frequent follow-up scans to reduce the risk of fractures that can be dangerous, even deadly.

robert bazell, nbc news, new york. up next here tonight, nearly one package for every person on the planet, a rare behind the scenes look at the shipping wars. i'm phil mickelson, pro golfer. if you have painful, swollen joints, i've been in your shoes. one day i'm on top of the world... the next i'm saying... i have this thing called psoriatic arthritis. i had some intense pain. it progressively got worse. my rheumatologist told me about enbrel. i'm surprised how quickly my symptoms have been managed. [ male announcer ] because enbrel suppresses your immune system, it may lower your ability to fight infections. serious, sometimes fatal events including infections, tuberculis, lymphoma, other cancers, and nervous system and blood disorders have occurred. before starting enbrel, your doctor should test you for tuberculosis and discuss whether you've been to a region where certain fungal infections are common. don't start enbrel if you have an infection like the flu. tell your doctor if you're prone to infections, have cuts or sores, have had hepatitis b, have been treated for heart failure, or if, while on enbrel, you experience persistent fever, bruising, bleeding, or paleness.

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starting today, it will cost you a penny more to put a letter in the mail. the price of a first class stamp now 45 cents. the increase expected to generate more than $800 million a year for the struggling u.s. postal service. much of the pain at the post office is due to more and more people using e-mail and other ways of communicating. it is also because of fierce competition from the folks at fedex and u.p.s., which deliver nearly 6.5 billion packages a year. cnbc's brian shactman went behind the scenes at both shipping giants to see exactly how they do it. >> reporter: fedex, it is not just a company, it's a verb. >> you aren't fedexing those bad boys? >> reporter: and how they go from this to this is nothing short of remarkable. understanding how you fedex and u.p.s. deliver a combined 25

million packages a day almost all of them on time begins at an airport. for fedex, it is the 800 acre suber hub in memphis. u.p.s.' megacomplex is in louisville, tennessee. both are a two-hour flight for most of the continental united states and can reach well beyond. it is after midnight and i'm inside a boeing 757 that just came to guadalajara, mexico, bringing all the cans out to go into the whirlpool for sorting. routing packages from one plane to another at break neck speed with almost no human hands. u.p.s. can sort up to 416,000 packages an hour. and in a night, a million. during a peak season like christmas, 1.6 million packages. getting them to the right place on time is so important in this internet retailing revolution that businesses like zappos and

pro flowers are popping up next to other companies. if an order comes in and it is too late to fulfill it, that's what this is for. >> really the pro flowers facility here in memphis is next to the fedex hub and it is the safety net for all of our orders for fulfillment the next day. >> reporter: despite all the innovation, from 155 miles of conveyor belts at u.p.s. to finger scanners at fedex, two recent embarrassing videos show that delivery is the most important step. for fedex it was a driver carelessly tossing a box over a fence. for u.p.s., an obscene gesture at a security camera. the public backlash proving at the end of the day, delivering packages still requires the proper human touch. brian shactman, cnbc, louisville, kentucky. >> you can watch brian's full report inside the package wars tomorrow night at 9:00, 8:00 central on cnbc. when we come back here tonight, she's a life saver, an extraordinary gift from a nurse to her patient. i remember the day my doctor told me i have an irregular heartbeat, and that it put me at 5-times greater risk of a stroke.

i was worried. i worried about my wife, and my family. bill has the most common type of atrial fibrillation, or afib. it's not caused by a heart valve problem. he was taking warfarin, but i've put him on pradaxa instead. in a clinical trial, pradaxa 150 mgs reduced stroke risk 35% more than warfarin without the need for regular blood tests. i sure was glad to hear that. pradaxa can cause serious, sometimes fatal, bleeding. don't take pradaxa if you have abnormal bleeding, and seek immediate medical care for unexpected signs of bleeding, like unusual bruising. pradaxa may increase your bleeding risk if you're 75 or older, have a bleeding condition like stomach ulcers, or take aspirin, nsaids, or bloodthinners, or if you have kidney problems, especially if you take certain medicines. tell your doctor about all medicines you take, any planned medical or dental procedures, and don't stop taking pradaxa without your doctor's approval, as stopping may increase your stroke risk. other side effects include indigestion, stomach pain, upset, or burning.

pradaxa is progress. if you have afib not caused by a heart valve problem, ask your doctor if you can reduce your risk of stroke with pradaxa. i thought i was invincible. i'm on an aspirin regimen now

because i never want to feel that helplessness again. [ male announcer ] be sure to talk to your doctor before you begin an aspirin regimen. talk to your doctor, and take care of what you have to take care of. finally tonight, an incredible story about a gift of giving that comes to us from atlanta, georgia. a young man hospitalized and in desperate need of a transplant and quickly running out of options. until an unexpected life saver stepped forward. here's nbc's thanh truong.

>> reporter: moments before life saving surgery, 23-year-old clay taber is getting tender reassurance from someone who could be his mother. >> i just said, thank you so much. i don't know how to repay you. >> reporter: not too long ago, they were perfect strangers. >> i have just complete faith in the surgical team. >> reporter: she's allison batsen, a nurse clay met while undergoing treatment for sudden kidney failure. >> i was freaking out. it was really scary. >> reporter: when no kidney donor could respond, allison responded by doing something stunning. she said she would be willing to go under the knife herself to donate one of her own kidneys. >> i thought that could be my son. and why not. i can do this. >> reporter: it turned out they were a match. the two bonded during his months at emory hospital, even meeting each other's families. the transplant team she was so used to working with would now operate on her. >> she said that, you know, clay, i want you to know that what we're doing here, i will have no regrets and whatever

happens, you know, i really want to do this for you. >> reporter: the transplant was successful. and both are now recovering. >> i just can't believe how selfless of a person she is. >> it is not about me. it is about clay. i'm really humbled by the whole experience. >> reporter: clay's case is even more remarkable when you consider that more than 96,000 americans are on the waiting list for a kidney transplant. more than 6,000 die each year, waiting for a kidney. something clay no longer has to worry about. thanks to allison, he now has a future and is planning his wedding. >> she is definitely going to be invited. i told her she will get to pick out the song and dance -- and we'll have a special dance. >> reporter: once strangers, now sharing a special connection for life. that's "nbc nightly news" for this sunday. brian williams will be here tomorrow. i'm lester holt reporting from