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new weapon to fight cancer
1. British scientists are preparing to launch trials of a radical new way to
fight cancer, which kills tumours by infecting them with viruses like the common
cold.
2. If successful, virus therapy could eventually form a third pillar
alongside radiotherapy and chemotherapy in the standard arsenal against cancer,
while avoiding some of the debilitating side-effects.
3. Leonard Seymour, a professor of gene therapy at Oxford University, who has
been working on the virus therapy with colleagues in London and the US, will
lead the trials later this year. Cancer Research UK said yesterday that it was
excited by the potential of Prof Seymour’s pioneering techniques.
4. One of the country’s leading geneticists, Prof Seymour has been working
with viruses that kill cancer cells directly, while avoiding harm to healthy
tissue. "In principle, you’ve got something which could be many times more
effective than regular chemotherapy," he said.
5. Cancer-killing viruses exploit the fact that cancer cells suppress the
body’s local immune system. "If a cancer doesn’t do that, the immune system
wipes it out. If you can get a virus into a tumour, viruses find them a very
good place to be because there’s no immune system to stop them replicating. You
can regard it as the cancer’s Achilles’ heel."
6. Only a small amount of the virus needs to get to the cancer. "They
replicate, you get a million copies in each cell and the cell bursts and they
infect the tumour cells adjacent and repeat the process," said Prof Seymour.
7. Preliminary research on mice shows that the viruses work well on tumours
resistant to standard cancer drugs. "It’s an interesting possibility that they
may have an advantage in killing drug-resistant tumours, which could be quite
different to anything we’ve had before."
8. Researchers have known for some time that viruses can kill tumour cells
and some aspects of the work have already been published in scientific journals.
American scientists have previously injected viruses directly into tumours but
this technique will not work if the cancer is inaccessible or has spread
throughout the body.
9. Prof Seymour’s innovative solution is to mask the virus from the body’s
immune system, effectively allowing the viruses to do what chemotherapy drugs do
- spread through the blood and reach tumours wherever they are. The big hurdle
has always been to find a way to deliver viruses to tumours via the bloodstream
without the body’s immune system destroying them on the way.
10. "What we’ve done is make chemical modifications to the virus to put a
polymer coat around it - it’s a stealth virus when you inject it," he said.
11. After the stealth virus infects the tumour, it replicates, but the copies
do not have the chemical modifications. If they escape from the tumour, the
copies will be quickly recognised and mopped up by the body’s immune system.
12. The therapy would be especially useful for secondary cancers, called
metastases, which sometimes spread around the body after the first tumour
appears. "There’s an awful statistic of patients in the west ... with malignant
cancers; 75% of them go on to die from metastases," said Prof Seymour.
13. Two viruses are likely to be examined in the first clinical trials:
adenovirus, which normally causes a cold-like illness, and vaccinia, which
causes cowpox and is also used in the vaccine against smallpox. For safety
reasons, both will be disabled to make them less pathogenic in the trial, but
Prof Seymour said he eventually hopes to use natural viruses.
14. The first trials will use uncoated adenovirus and vaccinia and will be
delivered locally to liver tumours, in order to establish whether the treatment
is safe in humans and what dose of virus will be needed. Several more years of
trials will be needed, eventually also on the polymer-coated viruses, before the
therapy can be considered for use in the NHS. Though the approach will be
examined at first for cancers that do not respond to conventional treatments,
Prof Seymour hopes that one day it might be applied to all cancers.
Questions 1-6
Do the following statements agree with the information given in the reading
passage? For questions 1-6 write
TRUE if the statement agrees with the information
FALSE if the statement contradicts the information
NOT GIVEN if there is no information on this in the passage
1.Virus therapy, if successful, has an advantage in eliminating
side-effects.
2.Cancer Research UK is quite hopeful about Professor Seymour’s work on the
virus therapy.
3.Virus can kill cancer cells and stop them from growing again.
4.Cancer’s Achilles’ heel refers to the fact that virus may stay safely in a
tumor and replicate.
5.To infect the cancer cells, a good deal of viruses should be injected into
the tumor.
6.Researches on animals indicate that virus could be used as a new way to
treat drug-resistant tumors.
Question 7-9
Based on the reading passage, choose the appropriate letter from A-D for each
answer.
7.Information about researches on viruses killing tumor cells can be
found
(A) on TV
(B) in magazines
(C) on internet
(D) in newspapers
8.To treat tumors spreading out in body, researchers try to
(A) change the body’ immune system
(B) inject chemotherapy drugs into bloodstream.
(C) increase the amount of injection
(D) disguise the viruses on the way to tumors.
9.When the chemical modified virus in tumor replicates, the copies
(A) will soon escape from the tumor and spread out.
(B) will be wiped out by the body’s immune system.
(C) will be immediately recognized by the researchers.
(D) will eventually stop the tumor from spreading out.
Questions 10-13
Complete the sentences below. Choose your answers from the list of words. You
can only use each word once.
NB There are more words in the list than spaces so you will not use them
all.
In the first clinical trials, scientists will try to ……10…… adenovirus and
vaccinia, so both the viruses will be less pathogenic than the ……11…….These
uncoated viruses will be applied directly to certain areas to confirm safety on
human beings and the right ……12…… needed. The experiments will firstly be
……13……to the treatment of certain cancers
1 There's a dimmer switch inside the sun that causes its brightness to rise
and fall on timescales of around 100,000 years - exactly the same period as
between ice ages on Earth. So says a physicist who has created a computer model
of our star's core.
2 Robert Ehrlich of George Mason University in Fairfax, Virginia, modelled
the effect of temperature fluctuations in the sun's interior. According to the
standard view, the temperature of the sun's core is held constant by the
opposing pressures of gravity and nuclear fusion. However, Ehrlich believed that
slight variations should be possible.
3 He took as his starting point the work of Attila Grandpierre of the Konkoly
Observatory of the Hungarian Academy of Sciences. In 2005, Grandpierre and a
collaborator, Gábor ágoston, calculated that magnetic fields in the sun's core
could produce small instabilities in the solar plasma. These instabilities would
induce localised oscillations in temperature.
4 Ehrlich's model shows that whilst most of these oscillations cancel each
other out, some reinforce one another and become long-lived temperature
variations. The favoured frequencies allow the sun's core temperature to
oscillate around its average temperature of 13.6 million kelvin in cycles
lasting either 100,000 or 41,000 years. Ehrlich says that random interactions
within the sun's magnetic field could flip the fluctuations from one cycle
length to the other.
5 These two timescales are instantly recognisable to anyone familiar with
Earth's ice ages: for the past million years, ice ages have occurred roughly
every 100,000 years. Before that, they occurred roughly every 41,000 years.
6 Most scientists believe that the ice ages are the result of subtle changes
in Earth's orbit, known as the Milankovitch cycles. One such cycle describes the
way Earth's orbit gradually changes shape from a circle to a slight ellipse and
back again roughly every 100,000 years. The theory says this alters the amount
of solar radiation that Earth receives, triggering the ice ages. However, a
persistent problem with this theory has been its inability to explain why the
ice ages changed frequency a million years ago.
7 "In Milankovitch, there is certainly no good idea why the frequency should
change from one to another," says Neil Edwards, a climatologist at the Open
University in Milton Keynes, UK. Nor is the transition problem the only one the
Milankovitch theory faces. Ehrlich and other critics claim that the temperature
variations caused by Milankovitch cycles are simply not big enough to drive ice
ages.
8 However, Edwards believes the small changes in solar heating produced by
Milankovitch cycles are then amplified by feedback mechanisms on Earth. For
example, if sea ice begins to form because of a slight cooling, carbon dioxide
that would otherwise have found its way into the atmosphere as part of the
carbon cycle is locked into the ice. That weakens the greenhouse effect and
Earth grows even colder.
9 According to Edwards, there is no lack of such mechanisms. "If you add
their effects together, there is more than enough feedback to make Milankovitch
work," he says. "The problem now is identifying which mechanisms are at work."
This is why scientists like Edwards are not yet ready to give up on the current
theory. "Milankovitch cycles give us ice ages roughly when we observe them to
happen. We can calculate where we are in the cycle and compare it with
observation," he says. "I can't see any way of testing [Ehrlich's] idea to see
where we are in the temperature oscillation."
10 Ehrlich concedes this. "If there is a way to test this theory on the sun,
I can't think of one that is practical," he says. That's because variation over
41,000 to 100,000 years is too gradual to be observed. However, there may be a
way to test it in other stars: red dwarfs. Their cores are much smaller than
that of the sun, and so Ehrlich believes that the oscillation periods could be
short enough to be observed. He has yet to calculate the precise period or the
extent of variation in brightness to be expected.
11 Nigel Weiss, a solar physicist at the University of Cambridge, is far from
convinced. He describes Ehrlich's claims as "utterly implausible". Ehrlich
counters that Weiss's opinion is based on the standard solar model, which fails
to take into account the magnetic instabilities that cause the temperature
fluctuations.
Questions 1-4
Complete each of the following statements with One or Two names of the
scientists from the box below.
Write the appropriate letters A-E in boxes 1-4 on your answer sheet.
A. Attila Grandpierre
B. Gábor ágoston
C. Neil Edwards
D. Nigel Weiss
E. Robert Ehrlich
1. ...claims there a dimmer switch inside the sun that causes its brightness
to rise and fall in periods as long as those between ice ages on Earth.
2. ...calculated that the internal solar magnetic fields could produce
instabilities in the solar plasma.
3. ...holds that Milankovitch cycles can induce changes in solar heating on
Earth and the changes are amplified on Earth.
4. ...doesn't believe in Ehrlich's viewpoints at all.
Questions 5-9
Do the following statements agree with the information given in the reading
passage?
In boxes 5-9 on your answer sheet write
TRUE if the statement is true according to the passage
FALSE if the statement is false according to the passage
NOT GIVEN if the information is not given in the passage
5. The ice ages changed frequency from 100,000 to 41,000 years a million
years ago.
6. The sole problem that the Milankovitch theory can not solve is to explain
why the ice age frequency should shift from one to another.
7. Carbon dioxide can be locked artificially into sea ice to eliminate the
greenhouse effect.
8. Some scientists are not ready to give up the Milankovitch theory though
they haven't figured out which mechanisms amplify the changes in solar
heating.
9. Both Edwards and Ehrlich believe that there is no practical way to test
when the solar temperature oscillation begins and when ends.
Questions 10-14
Complete the notes below.
Choose one suitable word from the Reading Passage above for each answer.
Write your answers in boxes 10-14 on your answer sheet.
The standard view assumes that the opposing pressures of gravity and nuclear
fusions hold the temperature ...10...in the sun's interior, but the slight
changes in the earth's ...11... alter the temperature on the earth and cause ice
ages every 100,000 years. A British scientist, however, challenges this view by
claiming that the internal solar magnetic ...12... can induce the temperature
oscillations in the sun's interior. The sun's core temperature oscillates around
its average temperature in ...13... lasting either 100,000 or 41,000 years. And
the ...14... interactions within the sun's magnetic field could flip the
fluctuations from one cycle length to the other, which explains why the ice ages
changed frequency a million years ago.
