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Scientists Work on a 'Smart Bomb' Against Cancer
Written by Cynthia Kirk

I’m Steve Ember with the VOA Special English Health Report.

 
Researchers tested a new cancer-fighting drug at Sasisekharan Laboratory at M.I.T.
Scientists have developed a new cancer drug.  So far, they have tested it only in laboratory animals.  The drug is designed to invade and kill cancer cells but not healthy cells. 

First, the drug enters the cancer and destroys the supply of blood.  Then it releases poison to destroy the cancer cells.  

Researchers at the Massachusetts Institute of Technology in Cambridge carried out the study.  The results appeared in Nature magazine.  A school news release called the drug an "anti-cancer smart bomb." 

Ram Sasisekharan is a professor at M.I.T.  He says his team had to solve three problems.  They had to find a way to destroy the blood vessels, then to prevent the growth of new ones.  But they also needed the blood vessels to supply chemicals to destroy the cancer.

So, the researchers designed a two-part "nanocell."  The cell is measured in nanometers, or one thousand-millionth of a meter.  The particle used was two hundred nanometers -- much, much smaller than a human hair. 

The scientists say it was small enough to pass through the blood vessels of the cancer.  But it was too big to enter normal blood vessels.  The surface of the nanocells also helped them to avoid natural defenses.

The scientists designed the cell as a balloon inside a balloon.  They loaded the outer part with a drug that caused the blood vessels to fall in on themselves.  That cut off the blood supply and trapped the nanocell inside the cancer.  Then, the nanocell slowly released chemotherapy drugs to kill the cancer cells.

The team says the treatment shrank the cancer and avoided healthy cells better than other treatments.  Untreated mice with cancer survived for twenty days.  The scientists say mice with the best current treatments lived thirty days.  But they say eighty percent of the mice treated with the nanocells lived more than sixty-five days.  

The study involved two different forms of cancer.  The team says the treatment worked better against melanoma, a deadly skin cancer, than against lung cancer.  However, more studies are needed before the new drug can be tested in humans.

This VOA Special English Health Report was written by Cynthia Kirk.  Our reports are on the Web at voaspecialenglish.com.  I’m Steve Ember.

Lessons Learned From the Atomic Bombings of Hiroshima and Nagasaki
Written by Jill Moss

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VOICE ONE:

I’m Steve Ember.

VOICE TWO:

 
Genbaku Dome in Hiroshima was one of the few structures left standing after August 6, 1945
And I’m Faith Lapidus with Explorations in VOA Special English.  Sixty years ago, the United States dropped atomic bombs on the Japanese cities of Hiroshima and Nagasaki.  Today we tell about those two events that ended World War Two.

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VOICE ONE:

Earlier this month, tens of thousands of people in Japan and around the world marked the sixtieth anniversary of the atomic bombings of Hiroshima and Nagasaki.  The United States dropped an atomic bomb on the southern Japanese city of Hiroshima on August sixth, nineteen forty-five.  More than seventy thousand people died as a result of the world’s first use of an atomic weapon. Three days later, a second bomb dropped on the city of Nagasaki killed an estimated eighty thousand civilians.  Tens of thousands of Japanese died later from radiation poisoning and other atomic-related diseases. 

VOICE TWO:

To honor victims of the attacks, more than fifty thousand people gathered in Hiroshima on August sixth.  Japanese officials and foreign diplomats also attended the early morning ceremony.  All mourners lowered their heads for a moment of silence at the exact moment of the Hiroshima bombing. The mayor of Hiroshima, Tadatoshi Akiba, called on the United Nations to take steps to put an end to nuclear weapons.  He criticized the countries with such weapons as threatening human survival.  A similar ceremony was held in Nagasaki on August ninth.  At both events, Japanese Prime Minister Junichiro Koizumi promised to keep Japan free of nuclear weapons.

VOICE ONE:

The atomic bombings of Hiroshima and Nagasaki led to the end of World War Two.  Japan informed the Allied Powers that it would surrender on August fourteenth, nineteen forty-five.  One day later, Emperor Hirohito officially announced the surrender on Japanese national radio.

Sixty years after the atomic bombings, historians are still debating if they were necessary to end the war.  At the time, fierce fighting in the Pacific continued and United States President Harry Truman was considering an invasion of Japan. 

VOICE TWO:

Some historians argue that millions of Japanese and American troops would have died in such an invasion.  Retired history professor Robert James Maddox wrote the book “Weapons for Victory: The Hiroshima Decision.”  He says America’s use of the atomic bomb was never in question.  Instead, President Truman had to decide when the bomb would be dropped.

VOICE ONE:

Other historians, however, question the morality of the decision.  Kai Bird wrote a book about American scientist J. Robert Oppenheimer, who is considered the father of the atomic bomb. He says even Mister Oppenheimer questioned the morality of the decision to use the bomb.  Some critics believe that Japan was about to surrender when President Truman decided to bomb Hiroshima and Nagasaki.  They say the real reason for the bombings was to send a message about America’s military strength to the Soviet Union. 

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Historians say war survivors in Asia remain angry over Japan’s fierce occupation during World War Two.  For almost four years, Japanese forces occupied much of Asia, from China to the Pacific islands.  Experts say Japanese soldiers killed many Asians unnecessarily.  Soldiers also sexually attacked many Asian women or used others as sex slaves.

Japan argued that its occupation was necessary to regain control of Asia from European and American governments. 

VOICE ONE:

Brian Farrell is a historian at the National University of Singapore.  He told VOA reporter Heda Bayron that many survivors are still angry at Japan.  In addition, Mister Farrell says Japan’s apparent lack of caring about its past cruelty has hurt its relations with other Asian nations. 

On August second, the Japanese parliament passed a resolution expressing deep regret for the suffering that Japan caused during the war.  Prime Minister Koizumi released a similar statement on August fifteenth, the official day of Japan’s surrender. The statement said Japan caused great damage and pain to the people of Asia through its colonization and aggression.  The statement expressed deep sadness and heartfelt apology. 

VOICE TWO:

Other recent issues have harmed Japanese ties with Asian nations.  Earlier this year, Japan approved new schoolbooks for history classes.  Critics say the books do not correctly describe the nation’s actions during World War Two.  Tensions have also increased over visits by Japanese officials to the Yasukuni memorial in Tokyo. The memorial honors Japanese soldiers who died during military service.  Critics say the memorial includes convicted war criminals.

VOICE ONE:

After the Hiroshima and Nagasaki bombings in nineteen forty-five, Japan became a strong anti-nuclear nation.  The attacks created a common feeling of opposition against atomic weapons.  Since nineteen fifty-six, it has been national policy not to have, manufacture or permit nuclear weapons in Japan. 

However, the country has a successful nuclear energy industry.  And lawmakers are starting to question whether Japan should create a nuclear defense system.  Kazuhiro Haraguchi is a Parliament member from the opposition Democratic Party.  He told VOA reporter Steve Herman that North Korea’s nuclear ability may soon force Japan to create its own nuclear weapons.  

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The world came very close to a nuclear war during the Cuban Missile Crisis in nineteen sixty-two.  For several days, the United States Navy blocked Cuba after discovering the Soviet Union had been shipping nuclear missiles to the country.  The crisis led to the nineteen sixty-eight Nuclear Non-Proliferation Treaty.  Today, about one hundred ninety countries have signed the international agreement.  In exchange for giving up nuclear weapons, they have promised to work toward nuclear disarmament. 

They also have agreed not to pass nuclear weapons to countries that do not have them. And they have agreed to share nuclear technology for peaceful energy purposes only.

VOICE ONE:

Today, seven nations in the world are known to have nuclear weapons -- Russia, China, India, Pakistan, France, Britain and the United States.  Most experts believe that Israel and North Korea also have nuclear weapons. 

Many of these nations have reduced their nuclear weapons. They include the United States, Russia, Britain and France. China is working to modernize its weapons program.  Libya has ended its program to develop nuclear weapons.  The International Atomic Energy Agency has taken apart Iraq’s program.  

VOICE TWO:

But some experts question whether the world is any safer.  In two thousand two, North Korea expelled inspectors from the International Atomic Energy Agency.  It has since admitted that it has a small number of nuclear weapons.  Talks among six nations urging North Korea to end its nuclear program have produced little progress.

The situation in Iran is also tense.  Earlier this month, Iran refused to honor international demands that it halt its nuclear program.  Iran restarted uranium-processing activities at its Isfahan nuclear center.  The International Atomic Energy Agency has called on Iran to suspend its nuclear activities. If it fails to do so, the IAEA could report Iran to the United Nations Security Council, which could order restrictions against the country.  Western nations suspect Iran is secretly trying to build nuclear weapons.  But Iran says it wants nuclear technology only to produce electricity.

VOICE ONE:

Some experts say the most frightening situation does not involve nations with nuclear weapons.  They say it involves terrorists with nuclear material.  Experts say terrorists could create a so-called “dirty bomb” with small amounts of radioactive and explosive material.  A more dangerous situation would involve a terrorist bomb fueled with a small amount of plutonium or highly enriched uranium.

This kind of weapon loaded into a small truck or boat could destroy a city and kill large numbers of people. Such an event could be like a second Hiroshima or Nagasaki.

These two Japanese cities have been largely rebuilt today.  But the lessons learned from their destruction sixty years ago remain.  J. Robert Oppenheimer may have described atomic weapons best.  He called them a great danger, but also the world’s greatest hope for lasting peace.  Only time will tell if he was right.

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This program was written by Jill Moss.  It was produced by Mario Ritter.  I’m Faith Lapidus.

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And I’m Steve Ember.  Join us again next week for Explorations in VOA Special English.
 

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