"There were many ups and downs, and moments over the years when we thought 'Can we do it? Should we continue? Or is it really just too tough?," he told Reuters, as data showing the success of his RTS,S vaccine were unveiled at an international conference on malaria.

"But today I feel fabulous. This is a dream of any scientist -- to see your life's work actually translated into a medicine ... that can have this great impact on peoples' lives. How lucky am I?"

Final stage clinical trial data on RTS,S, also known as Mosquirix, showed it halved the risk of African children getting malaria, making it likely to become the world's first successful vaccine against the deadly disease.

While scientists say it is no "silver bullet" and will not end the mosquito-borne infection on its own, it is being hailed as a crucial weapon in the fight against malaria and one that could speed the path to eventual worldwide eradication.

Malaria is caused by a parasite carried in the saliva of mosquitoes. It kills more than 780,000 people per year, most of them babies or very young children in Africa.

Cohen's vaccine goes to work at the point when the parasite enters the human bloodstream after a mosquito bite. By stimulating an immune response, it can prevent the parasite from maturing and multiplying in the liver.

Without that immune response, the parasite re-enters the bloodstream and infects red blood cells, leading to fever, body aches and, in some cases, death.

Although Cohen's scientific work has been largely in Belgium, where he runs a GSK laboratory, the final-stage trials of RTS,S were conducted in Africa, where malaria hits hardest.

With GSK working in partnership with the non-profit PATH Malaria Vaccine Initiative (MVI), the trials became Africa's largest-ever medical experiment as the vaccine was tested in around 16,000 children across seven countries.

Cohen said that if all goes to plan, RTS,S could be licensed and rolled out by 2015.

SOUL SEARCHING

As he looks back at the vaccine's long, slow development, the bearded 68-year-old molecular biologist laughs at how naive he was when he first agreed to take on the task.

It was April 1, 1987 when his boss at the drug company, then called Smith, Kline & French, asked him to be head of the malaria vaccine research programme, just after an early-stage experimental vaccine and failed a test.

"Unfortunately, it was not a great success. Only one volunteer out of the several that were vaccinated was actually protected. So, after quite a bit of optimism, there was then quite a bit of soul searching," Cohen said.

"I did not actually know much about malaria, apart from about the enormous medical burden it represented. But I felt I was taking on an enormous scientific challenge, and that was exciting for a relatively young scientist."

Having come from academia and post-doctorate studies into what he said were "sometimes esoteric questions" of molecular biology, he was also attracted by the prospect of doing something "very meaningful" in terms of global health.

Getting on for a quarter of a century later, Cohen said he had "never dreamed it would take this long".

He was also careful to underline that this was a first step, as well as a world first. GSK, MVI and several other research groups and drug firms are already working on next generation vaccines and on other ways of making malaria shots they hope will better the roughly 50 percent success rate of RTS,S.

"The work is not over, that is for sure," Cohen said.

REUTERS - Men are diagnosed with breast cancer at less than one percent the rate of women, but when they are the disease is often more advanced on average, and they are more likely to die from it, according to an international study.

Researchers led by Mikael Hartman at the National University of Singapore combined cancer registries from Denmark, Finland, Norway, Sweden, Singapore and Geneva, Switzerland, with cases dating back to 1970.

The data included about 460,000 women diagnosed with breast cancer, and about 2,700 men.

Men were more likely to have the disease that had spread beyond the breast by the time they were diagnosed. In treatment, they had less surgery and radiation than women but similar rates of chemotherapy and hormone treatment.

Over the entire time period, men had a 72 percent chance of surviving breast cancer in the five years after a diagnosis, compared to 78 percent in women.

"Men who develop a breast lump delay seeing their doctor longer than a comparable woman with similar symptoms," Hartman said in an email to Reuters Health.

"Male breast cancer is rare but men can develop the disease and should be aware that they should seek care if a breast lump develops."

His team said in the Journal of Clinical Oncology that previous studies have shown that it typically takes a few months from when men start getting symptoms until they are diagnosed with breast cancer.

Men are most commonly in their 60s or 70s when diagnosed, according to the U.S. National Cancer Institute. Radiation exposure and diseases that increase estrogen levels, such as liver cirrhosis or the genetic disorder Klinefelter syndrome, are among the factors that raise a man's risk.

"It's not surprising that men with breast cancer present with later stages," said Susan Dent, from the Ottawa Hospital Cancer Centre in Canada, who was not involved in the study.

"That's just because the awareness of the fact that breast cancer can occur in men is just not as acute. Men aren't as likely to think of it, and health care providers aren't as likely to think of men having breast cancer."

Men should be particularly aware of breast cancer, and possibly consider getting screened for it, if they have a family history of the disease, including a predisposition to cancer caused by mutations in the BRCA1 and BRCA2 genes, which are well known to raise women's risk of breast and ovarian cancers, she added.

Because of recommendations for regular mammograms in women starting in their 40s or at age 50, depending on the country, many cancers are caught in women before they have any symptoms.

But the United States Preventive Services Task Force, a federally-supported panel that sets guidelines for cancer screening, does not recommend regular breast cancer screening in men without symptoms.

"In total, male breast cancer is still a rare event. Never would I recommend that all men routinely go out and get screened," said Dent. SOURCE: http://bit.ly/n3B9oU

(Reporting from New York by Genevra Pittman at Reuters Health; Editing by Elaine Lies and Yoko Nishikawa)

LAS VEGAS: British IndyCar driver Dan Wheldon died from injuries sustained in an horrific crash at the Las Vegas Motor Speedway on Sunday, race organisers said.

The 33-year-old Englishman, who lived in St. Petersburg Florida, was involved in a multi-car accident 13 laps into the Las Vegas Indy 300 which sent his vehicle flying.

Wheldon was flown by helicopter to University Medical Center in Las Vegas for treatment before his death was announced two hours later.

DUBAI (Reuters) - A television station based in Syria that supports Muammar Gaddafi confirmed Monday that the deposed Libyan leader's son Khamis had died in fighting southeast of the capital Tripoli on August 29.

Khamis commanded an elite military brigade and his death marked the highest-profile pro-Gaddafi casualty since the uprising began that ended Gaddafi's 42 years in power.

Arrai television announced Khamis's death, along with that of his cousin Mohammed Abdullah al-Senousi, Gaddafi's intelligence chief, saying they were killed during a battle with National Transitional Council (NTC) forces in the city of Tarhouna, 90 km (60 miles) southeast of Tripoli.

The TV station, which has broadcast audio messages from Gaddafi and his spokesman since the Libyan capital was overrun by NTC forces in August, posted pictures of Khamis and Senousi and broadcast verses of the Koran, the traditional way of mourning.

It said Khamis and Senousi died "while confronting the enemies of their homeland" on August 29.

NTC military officials had said in August that Khamis was killed in Tarhouna and buried in the city of Bani Walid but there was no confirmation at the time from Gaddafi loyalists.

Khamis had been reported dead twice before during the uprising, only to reappear.

A U.S. official, speaking on condition of anonymity, told Reuters the United States could not yet independently confirm Khamis's death but said similar information was being received in Washington from "reliable sources."

SIRTE (Reuters)- Libyan government fighters battled on Sunday to subdue pockets of resistance by pro-Gaddafi fighters, whose refusal to abandon the ousted leader's hometown of Sirte is delaying Libya's move to democracy.

Ruling National Transitional Council (NTC) forces kept up their bombardment of a small area in the centre of Sirte but there was no push under way from ground troops.

NTC militia have besieged Sirte for weeks, slowly boxing Gaddafi die-hards into an area about two square kilometres (a square mile). Green flags, the symbol of Gaddafi's rule, still fly over the area.

Some fighters expressed irritation with their commanders for failing to order and advance and poor communication between brigades.

"There are no orders coming in even though we have the power to push them out," Hesham al-Dafani, an NTC fighter, told Reuters. "We don't know what's happening."

The failure to seize Sirte -- and the other remaining Gaddafi holdout, Bani Walid -- has delayed Libya's democratic transition. The country's new rulers say the process will only begin once Sirte is captured.

Fighting also continued in Bani Walid on Sunday, Reuters reporters said, with sniper fire hindering an NTC advance into the city just as it has in Sirte.

Some fighters in Sirte said they suspected that the failure to order an advance was a result of NTC leaders not yet being ready to set out a roadmap for national elections.

Other fighters blamed the delay on a lack of communication between different NTC militias in Sirte.

"We are civilians, we not military people," NTC field commander, Mohammed al Sabty, said. "We don't have a certain plan."

NTC fighters continued to fire on an area known as Neighbourhood Two and said they believed one of Gaddafi's sons, Mo'tassim, could be holed up there.

"We know that Gaddafi's Mo'tassim is inside, that's why they are fighting to the last drop of blood," commander Omar Abu Lifa said. "We're surrounding that area. We are taking it slowly because we want to catch him alive."

Some NTC sources told Reuters last week Mo'tassim, a former national security advisor, had been captured as he tried to escape Sirte. But the ruling NTC has yet to officially confirm, or deny, the reports.

NTC officers say Gaddafi loyalists continue to hold out because they fear reprisals if they surrender. Some captured fighters have been abused, rights groups say.

A doctor for the medical aid charity Medecins Sans Frontieres in Sirte has estimated 10,000 people remain trapped in the city of 75,000 residents. Many are women and children, some are sick or injured.

GADDAFI HOME BULLDOZED

Some political analysts say the long sieges of Sirte and Bani Walid risk undermining the NTC which and frustrate its effort to control the whole country.

The often chaotic struggle for Sirte has killed scores of people, left thousands homeless and laid waste to much of what was once a showpiece Mediterranean city where Gaddafi enjoyed entertaining foreign leaders.

The dangers posed by the failure to capture Gaddafi were highlighted on Friday when fighting erupted in Tripoli between NTC forces and Gaddafi-loyalists for the first time since he fled the city in August.

Government forces set up more roadblocks across the city over the weekend, but especially in and around Abu Salim, an area of run-down apartment blocks where the clashes took place.

The area remained calm on Sunday amid the heavy security but, nearby, a group of armed men with two bulldozers began demolishing the walls around Gaddafi's former home.

As the bulldozers set about the Bab al-Azizyah compound, a heavily fortified construction spread over six sq-km (2.3 sq miles) that symbolised his repressive rule, men chanted, "God is greatest. This is for the blood of the martyrs."

Some fired machineguns into the air.

"We are destroying it because we want to demolish anything that belongs to Gaddafi," one gunman, Essam Sarag, told Reuters.

People driving past stopped their cars and joined a crowd waving new Libyan flags.

"We will continue until we destroy everything that belongs to Gaddafi," said Etman Lelktah, who said he was in charge of the fighters at the scene.

"We ask that a peace organisation be built instead of Gaddafi's place."

(Additional reporting by Haydar Zim in Bani Walid and Yasmine Saleh in Tripoli; Writing by Barry Malone; Editing by Jon Boyle)

HONG KONG (Reuters) - Plants and animals are shrinking because of warmer temperatures and lack of water, researchers said on Monday, warning it could have profound implications for food production in years ahead.

"The worst-case scenarios ... are that food crops and animals will shrink enough to have real implications for food security," Assistant Professor David Bickford, of the National University of Singapore's biological sciences department, said.

Bickford and colleague Jennifer Sheridan trawled through fossil records and dozens of studies which showed that many species of plants and creatures such as spiders, beetles, bees, ants and cicadas have shrunk over time in relation to climate change.

They cited an experiment showing how shoots and fruit are 3 to 17 percent smaller for every degree Celsius of warming in a variety of plants.

Each degree of warming also reduces by 0.5 to 4 percent the body size of marine invertebrates and 6 to 22 percent of fish.

"Survival of small individuals can increase with warmer temperatures, and drought conditions can lead to smaller offspring, leading to smaller average size," they wrote in their paper which was published in the journal, Nature Climate Change, on Monday.

"Impacts could range from food resources becoming more limited (less food produced on the same amount of land) to wholesale biodiversity loss and eventual catastrophic cascades of ecosystem services," Bickford wrote.

"We have not seen large-scale effects yet, but as temperatures change even more, these changes in body size might become much more pronounced - even having impacts for food security."

(Reporting by Tan Ee Lyn; Editing by Nick Macfie)

SANAA (Reuters) - Eight Yemenis, including five protesters, were killed in a new upsurge in violence in the capital on Sunday, hospital officials and witnesses said, and President Ali Abudllah Saleh said he expected China and Russia to block U.N. moves to end his rule.

The two countries joined forces to veto a European-sponsored resolution against Syria earlier this month but were not expected to block the resolution on Saleh which is due to go to the Security Council this week, diplomats in New York have said.

Yemeni security forces fired on protesters, killing at least five people in the capital Sanaa on Sunday, hospital officials said, in violence which took the death toll in two days to at least 20.

Two brothers and a nephew died in a separate incident in Sanaa when a shell fell on their house in al-Qaa neighbourhood, witnesses said. They said the shell exploded during clashes between security forces and anti-government fighters.

Witnesses said security forces attacked the protesters when they tried to enter Zubayri Street, which lies between areas controlled by government forces and dissident general Ali Mohsen.

Residents said the authorities feared protesters could block off the street, a major throughway for traffic.

"Until now, we have four martyrs and 13 injured by bullets," said Dr. Muhammad al-Qubati, head of a field hospital set up by protesters on Sixty Street in the capital Sanaa, where thousands have camped out for months demanding Saleh end his 33 years in office.

Security forces also killed a 52-year-old woman during protests in the southern city of Taiz, medical officials said.

SURGE IN VIOLENCE

Violence in Yemen, strategically located at the southern tip of the Arabian Peninsula, has surged over the last two days, with security forces killing at least 12 on Saturday while al Qaeda insurgents blew up a gas pipeline, halting the impoverished nation's gas exports.

U.N. Security Council members are considering a resolution expected to urge Saleh to hand over power under a Gulf Cooperation Council (GCC) peace plan.

Saleh says he is ready to step down but wants to ensure that control of the country is put in safe hands.

"Some friendly states, permanent members of the (Security Council) such as China and Russia, will not take a hardline position like some other permanent members," Saleh said in comments broadcast on Yemeni state television.

Speaking at a meeting of his security and military chiefs in Sanaa, he said Western permanent members of the Security Council based their decisions on information gathered solely from the opposition.

"They consider the opposition as being aggrieved and that it should be supported," he said.

Britain has been drafting the resolution in consultation with France and the United States and intends to circulate it to the full 15-nation Security Council shortly after a closed-door meeting on Tuesday.

Yemeni officials have said the attack on the pipeline on Saturday was in retaliation for the killing of the head of the media department of al Qaeda in the Arabian Peninsula in an air raid on militant outposts in Yemen last week.

The U.S. and Saudi Arabia, which shares a border with Yemen, fear al Qaeda is trying to take advantage of the country's political vacuum to expand its territory in the south of the Arabian Peninsula, near a strategic shipping strait used by tankers carrying some 3 million barrels of oil a day.

(Reporting By Mohammed Sudam; writing by Nour Merza; editing by Sami Aboudi and Philippa Fletcher)

BAGHDAD (Reuters) - Just weeks before U.S. troops plan to leave Iraq, the country's political elite and Washington are at odds over whether American soldiers stay as trainers: Baghdad rejects any legal immunity for U.S. soldiers and Washington says that means no deal.

Without a shift in Iraq's position, any accord will likely now fall somewhere in between as Iraq's political stalemate, U.S. domestic opposition to the war and a lack of time force a deal that leaves a just few hundred American soldiers in Iraq.

Iraqi Prime Minister Nuri al-Maliki last week said U.S. troops could stay on as part of the small NATO mission or as part of an already existing U.S. embassy military training programme which would give American troops legal protections.

The country's political leadership gave Maliki the green light to negotiate, but without immunity -- a sensitive matter that would have required tricky horse-trading within his fragile cross-sectarian government and possible defeat in parliament.

But Washington sounds skittish on the options, insisting U.S. troops would need full protections or at least assurances that whatever Iraq offers would bring the same legal cover.

"I can't see the United States agreeing to blanket Iraqi jurisdiction," said Stephen Biddle at the Council on Foreign Relations. "If it is more than just brinkmanship and if they are going to insist on this, then I think the United States will decline to stay at all."

More than eight years after the U.S.-led invasion that ousted Saddam Hussein, around 41,000 troops are in Iraq mostly advising Iraqi forces since ending combat operations last year.

While violence has fallen since the sectarian slaughter in 2006-2007, Iraq still suffers daily attacks from a stubborn insurgency allied with al Qaeda and from Shi'ite militia.

In private some Iraqi leaders acknowledge they would like a U.S. troop presence as a guarantee in a country where sectarian tensions still simmer and Iraqi Arabs and Kurds are in dispute over who controls oil-rich areas in the north of Iraq.

Only anti-U.S. Shi'ite cleric Moqtada al-Sadr openly opposes a continued U.S. presence. His militia once battled U.S. troops, but he is now a key political ally for Maliki. His opposition to U.S. troops complicates the Iraqi leader's position.

Maliki says Iraq needs fewer than the 3,400 troops U.S. officials requested. But his alternatives leave little room for Washington.

The embassy's Office of Security Cooperation-Iraq or OSC-I already has trainers covered by diplomatic immunity as part of the State Department. Attaching more uniformed officers maybe the most viable option, but numbers would likely be limited.

"Under this agreement it could be just 200, or 300," said Iraqi lawmaker Sami al-Askari, a Maliki ally. "They have no option. The alternative is for them to leave altogether."

SENSITIVE ISSUE

Immunity is a sensitive issue for many Iraqis who remember abuses committed by U.S. forces and contractors during the worst years of the war. U.S. soldiers in other countries also have the kind of legal protections Washington wants in Iraq.

Under the current deal, U.S. soldiers come under U.S. jurisdiction for certain crimes committed on duty.

Bringing U.S. troops under the umbrella of the small NATO training mission in Iraq could also provide Americans with legal protections. But that option brings its own problems.

NATO has fewer than 200 staff involved in training such as police work and logistics in the mission set to end in 2013. Iraqi lawmakers are now discussing a bill to expand the NATO programme and allow some U.S. troops to stay.

But that may not be enough for Washington and it could face resistance from NATO countries worried it would attract hostility against U.S. troops to the more low-key NATO operation.

"Lots of people here are likely to find that even less reassuring than if our military folks were part of the U.S. diplomatic mission," David Mack, Middle East Institute Scholar and former U.S. ambassador.

POLITICAL "DRIFT"

Iraqi and U.S. officials say Iraq's armed forces are more capable now of containing the country's stubborn insurgency. But they acknowledge their military still needs training in areas such as air defence, logistics and intelligence gathering.

Even without military trainers, hundreds of American civilian contractors will be going to Iraq to help Iraqi forces train up on hardware such as F-16 fighter jets.

Some in Washington see a strong U.S. presence in Iraq as essential for stability and as a buffer against Iran's influence. Defence hawks such as Senator John McCain say more than 10,000 U.S. troops may be needed in Iraq.

But a shift in Baghdad's position now looks difficult. Iraq's political process is already mired in squabbling among Shi'ite, Sunni and Kurdish blocs that make up the power-sharing government.

"The risk is that you are at a tipping point where we are at the withdrawal date and they will negotiate a few trainers and that is all there will be," one Western diplomat said. "No one has the political courage to grip this and it will just drift."

Still, when the United States and Iraq negotiated their 2008 security agreement, talks dragged for almost a year. Iraqi sovereignty, immunity and a date for withdrawal complicated negotiations before the final security agreement was signed.

"U.S. troops will almost certainly stay," said Gala Riani at IHS Global Insight. "But the technicalities are still important for reassuring the Iraqi public and critical parties."