Although exposure to asbestos is the primary cause of mesothelioma, a slow-developing
cancer, researchers believe that infection by the SV40 virus is a contributing cause, since
in the United States 60 percent of tissue samples from mesotheliomas, but none from
healthy tissue, contain SV40. SV40 is a monkey virus; however, in 1960 some polio
vaccine was contaminated with the virus. Researchers hypothesize that this vaccine was
the source of the virus found in mesotheliomas decades later.
Which of the following, if true, most strongly supports the researchers’ hypothesis?
A. SV40 is widely used as a research tool in cancer laboratories.
B. Changes in the technique of manufacturing the vaccine now prevent
contamination with SV40.
C. Recently discovered samples of the vaccine dating from 1960 still show traces of
the virus.
D. In a small percentage of cases of mesothelioma, there is no history of exposure to
asbestos.
E. In Finland, where the polio vaccine was never contaminated, samples from
mesotheliomas do not contain SV40.
For discussion. OA to follow
SV40
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IMO E
SV40 -------Mesotheliomas.....
60% Tissues from Mesotheliomas ----SV40....
However , in1960... Polio Vaccine was contaminated with SV40....So ....Polio Vaccine was the source...
E direclty supports the researchers hypothesis...by mentioning a place where polio vaccine was not contaminated and the samples from mesotheliomas there did not contain SV40....
SV40 -------Mesotheliomas.....
60% Tissues from Mesotheliomas ----SV40....
However , in1960... Polio Vaccine was contaminated with SV40....So ....Polio Vaccine was the source...
E direclty supports the researchers hypothesis...by mentioning a place where polio vaccine was not contaminated and the samples from mesotheliomas there did not contain SV40....
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IMO: D
There are two conclusion in the above text, first is that the cancer development is aided by the virus, and the second claim is that the virus is spread from the infected vaccine.
The second conclusion is supported by both C & E. However , E contradicts the first conclusion while supporting the second conclusion. But I think the main conclusion here is the first one and it is being supported by D.
Experts please comment....
There are two conclusion in the above text, first is that the cancer development is aided by the virus, and the second claim is that the virus is spread from the infected vaccine.
The second conclusion is supported by both C & E. However , E contradicts the first conclusion while supporting the second conclusion. But I think the main conclusion here is the first one and it is being supported by D.
Experts please comment....
Ananda Chakraborty
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OA is E, i too fell for the C trap but later realised that even if traces of virus are found in the vaccine that does not proof its cause for the disease in patients it just re-affirms the contamination mentioned.
In E,
its like showing when cause does not occur the effect does not occur hence strengthens
In E,
its like showing when cause does not occur the effect does not occur hence strengthens
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Me too.
Breaking down the stimulus, I agree that C is not the correct answer as it doesnt talk anything about the cause. It just affirms that traces polio vaccince has SV40 virus (supporting the premise)
C - SV40 virus --> Mesothelioma
P1 - 60 percent of tissue samples from mesotheliomas contain SV40 virus
P2 - In 1960, some polio vaccine was contaminated with the virus.
OA - E coz it states NO SV40 virus --> NO Mesothelioma. But I eliminated this as it appeared to be a mistaken negation. Any thoughts why it is not a mistaken negation?
Breaking down the stimulus, I agree that C is not the correct answer as it doesnt talk anything about the cause. It just affirms that traces polio vaccince has SV40 virus (supporting the premise)
C - SV40 virus --> Mesothelioma
P1 - 60 percent of tissue samples from mesotheliomas contain SV40 virus
P2 - In 1960, some polio vaccine was contaminated with the virus.
OA - E coz it states NO SV40 virus --> NO Mesothelioma. But I eliminated this as it appeared to be a mistaken negation. Any thoughts why it is not a mistaken negation?