Multiple sclerosis: Difficult CR

[loveusonu]

Multiple sclerosis is an autoimmune disease: white blood cells attack the myelin sheath that protects nerve fibers in the spinal cord and brain. Medical science now has a drug that can be used to successfully treat multiple sclerosis, but the path that led medical researchers to this drug was hardly straightforward. Initially, some scientists believed attacks characteristic of multiple sclerosis might be triggered by chronic viral infections. So in 1984 they began testing gamma interferon, one of the body's own antiviral weapons. To their horror, all the multiple sclerosis patients tested became dramatically worse. The false step proved to be instructive however.

Which of the following is LEAST compatible with the results of the gamma interferon experiment?
(A) Gamma interferon stops white blood cells from producing myelin-destroying compounds.
(B) Administering gamma interferon to those without multiple sclerosis causes an increase in the number of white blood cells.
(C) Medical researchers have discovered that the gamma interferon level in the cerebrospinal fluid skyrocket just before and during multiple sclerosis infections.
(D) It has now been established that most multiple sclerosis sufferers do not have chronic viral infections.
(E) The drug now used to treat multiple sclerosis is known to inhibit the activity of gamma.


OA: later

[Shawshank]

IMO -- C

Tough onr..good.queston

[gmat1011]

I think the least compatible is a

Gamma-whatever encourages the production of WBCs which attack the myelin sheath. Thats why the people with the disease who were tested for Gamma/administered Gamma got worse...

b may or may not be compatible as the question does not tell us what happens if Gamma is tested on those who do not have Multiple sclerosis

c-e only seem to point out in different ways that gamma is the culprit for causing the disease (so these seem compatible)

[hardik.jadeja]

I pick A.

If Gamma interferon stops white blood cells from producing myelin-destroying compounds, then it should be a good thing since myelin sheath protects nerve fibers in the spinal cord and brain. But Gamma interferon is supposed to worsen Multiple sclerosis. So option A is not consistent with the information given in the passage.

[dkumar.83]

Can anyone explain the answer?

[FightWithGMAT]

Multiple sclerosis is an autoimmune disease: white blood cells attack the myelin sheath that protects nerve fibers in the spinal cord and brain. Medical science now has a drug that can be used to successfully treat multiple sclerosis, but the path that led medical researchers to this drug was hardly straightforward. Initially, some scientists believed attacks characteristic of multiple sclerosis might be triggered by chronic viral infections. So in 1984 they began testing gamma interferon, one of the body's own antiviral weapons. To their horror, all the multiple sclerosis patients tested became dramatically worse. The false step proved to be instructive however.

Which of the following is LEAST compatible with the results of the gamma interferon experiment?
(A) Gamma interferon stops white blood cells from producing myelin-destroying compounds.
(B) Administering gamma interferon to those without multiple sclerosis causes an increase in the number of white blood cells.
(C) Medical researchers have discovered that the gamma interferon level in the cerebrospinal fluid skyrocket just before and during multiple sclerosis infections.
(D) It has now been established that most multiple sclerosis sufferers do not have chronic viral infections.
(E) The drug now used to treat multiple sclerosis is known to inhibit the activity of gamma.


OA: later

Tricky one though!!!!

IMO A. Could reach only by POE.

Result of gamma interferon experiment-->MS patients become worse-- That means Viral infection is not cause of the disease--->>either gamma interferon itself or some other factor was the cause of the disease.

least compatible = least support to the result of the experiment
Now:
A--> suggests that absence of GI encourages WBC to attack myelin sheath-------> that means GI is not responsible for the disease, but WBC are.
B--> suggests that GI increases WBC count and, in turn, is indirectly responsible for the damage of myelin sheath
C--> suggests that excess of GI may be the cause of the disease.
D--> suggests that viral infections is not the cause of the disease
E--> suggests that drug acts on GI, treating the disease--> means GI may be the cause of the disease

[Testluv]

received a pm.

Step 1 of the Kaplan method tells us to begin with the question stem. The question stem tells us to select a choice that is "LEAST compatible".

On any standardized test, we should read "LEAST" as "IS NOT", or "DOES NOT". (Just as we read "most" as "does" or "is" in stn/wkn question stems).

So, the question is asking for something that IS NOT compatible with the passage. Therefore, the four wrong answers will be things that ARE compatible with the passage. That is, the four wrong answers are things that could be true based on the passage. The right answer is something that must be false based on the passage. So, this is an inference-family question (NOT strengthen or weaken!)

And the question would have been the same had it read:

"If all of the above statements are true, which of the following must be false?"

In the passage, we learn that multiple sclerosis (MS) involves white blood cells attacking the myelin sheath. Towards the end of the passage, we learn that gamma-interferon actually made MS worse (to the scientists' horror).

Well, if those 2 things are true, then choice A must be false. If gamma interferon stopped the white blood cells from attacking the myelin, then gamma interferon would have alleviated MS (rather than exacerbate it).

Having characterized the nature of the correct answer during step 1 (ie, it is a must be false question), and having found that choice A must be false, a confident Kaplan-trained student would select choice A wthout even looking at the other choices (there can only be one correct answer)....that's what I did

(However, if anyone has any questions about the other choices, I will certainly look at them!)