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  #1  
Old 02-17-2012
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Arrow NBME 2, Block 2 discussion....

Question 21:

55 year old man is hospitalized after having a stroke. The patient most likely has which of the following signs on the right??

I picked B. Weakness of the upper limb and aphasia. Confirm if its right.


Question 27:

68 year old woman admitted for evaluation of gross hematuria. 2 days after admission she develops aphasia and right hemiplegia followed shortly by coma and death.

I picked B. Papillary necrosis. Confirm if its right.


Question 33:

57 year old man receives sintered titanium oxide implant during total hip arthroplasty followin traumatic injury. During first 6 weeks following surgery, bone ingrowth anneals to the bone-metal interface in both the femur and acetabulum, thus securing the prosthesis in position. Type 1 collagen secretion in the first stage of matrix formation is mediated by which of the following cell types?

A) chondroblasts
B)chondrocytes
C)endothelial cells
D)macrophages
E) osteoblasts
F)osteoclasts
G)osteocytes


QUESTION 35:

Hep B virus is major cause of hepatocellular carcinoma. Enzyme involved at step 2 is most likely to be???

I pick RNA polymerase. Confirm if its right.


QUESTION 43:

a neonate has a murmur at the apex, which is a normal transient finding in up to 50% newborns. Which of the following actions concerning informing the parents about the murmur in most appropriate?

A) defer telling the parents and order an echo
B) defer telling the parents because heart murmurs often resolve
C) defer telling the parents but order a cardio consult
D) tell the parents and examine the infant again in 24 hrs
E) tell the parents that this finding is normal but offer a cardio consult
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  #2  
Old 02-17-2012
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I also had problem with these same questions.
So lets discuss one by one

For 21 the brain lesion is of right parietal region and i choose B but i think since lateral ventricle is visible so the lesion ia around the middle of homunculus which will most probably not involve the lower limb so only two options are left B and E dont know now how its E......
Lets other throw light on this


For 27 i marked F but hte answer in the Key is E but i think F is correct reason behind it is it has history of aphasia and hemiplegia also there is haemorrhagic kidney in the slide.Most probably it is renal infarct

33 i choose chondroblast dont know why osteoblast.

35 yes you are right for step 2 RNA polymerase and Step 3 RT.
Key is wrong here

43 I choose E but it says D dont have any idea let people explain further.
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Quote:
Originally Posted by jinni View Post
For 21 the brain lesion is of right parietal region and i choose B but i think since lateral ventricle is visible so the lesion ia around the middle of homunculus which will most probably not involve the lower limb so only two options are left B and E dont know now how its E......
Lets other throw light on this
The way I saw it is that the lesion is on the left and also on the outside. Clearly will affect upper limb and since it is on the left (dominant hemisphere) in the same area as speech areas it will cause aphasia. Now if it was on the right then it would cause dysarthria.

What do you think???


Quote:
Originally Posted by jinni View Post
For 27 i marked F but hte answer in the Key is E but i think F is correct reason behind it is it has history of aphasia and hemiplegia also there is haemorrhagic kidney in the slide.Most probably it is renal infarct
It is a classic picture of Renal Papillary necrosis. Look in google images and you will see the exact same type of pictures. There are ring defect all over the cortex where the papilla used to be and there is sudden gross hematuria. Malignant HTN would be a cause of this, which also caused a rupture in the circle of willis causing a left middle cerebral artery hemorrage.

What do you think???


Quote:
Originally Posted by jinni View Post
33 i choose chondroblast dont know why osteoblast.
Chondroblasts make collagen in cartilage. Since this is bone I will say it is the osteoblast that makes the cartilage here.


Quote:
Originally Posted by jinni View Post
43 I choose E but it says D dont have any idea let people explain further.
I don't even know what the murmur represents first of all, is it a PDA????

this one I can't pick between D and E. Both seem right to me. Maybe someone else could jump in and help us out.
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  #4  
Old 02-17-2012
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For Qs 21 ......ans E looks correct ....... looking at the section of brain you can easily recognize that its a section through the lower half NOT the UPPER half means the part near where lateral ventricle ends into the 3rd ventricle ....... now look at the homunculus diagram in FA at pg 403 .... here you will realize that the UL area is free from damage as its pretty much on the top ... so it will affect the muscles of the face and cause dysarthria ..

Qs 27 ans renal infarction is correct as a pale area on the border of the kidney plus history of hemiplegia ..... F is correct .....

Qs 33 ans is osteoblast ..... they are the one that form new bone ... chondrocytes form cartilage

Qs 35 the ans is RNA polymerase

Qs 43 ans is D i feel , because the Qs has a hint saying normal transient finding in up to 50% newborns so it is not completely normal so you cannot say it normal , but still take a cardiac consultation ...

so you should tell the patient what excatly they have told us in the stem and check again after 24 most suitable ans ........


please could you explain Qs 10 , 25 , 39 , 49 .......

thanks
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Quote:
Originally Posted by Hitman View Post
For Qs 21 ......ans E looks correct ....... looking at the section of brain you can easily recognize that its a section through the lower half NOT the UPPER half means the part near where lateral ventricle ends into the 3rd ventricle ....... now look at the homunculus diagram in FA at pg 403 .... here you will realize that the UL area is free from damage as its pretty much on the top ... so it will affect the muscles of the face and cause dysarthria ..
Ok I get the part where it is paralysis of the face, but then it is in the exact location of the speech areas in the dominant LT side. can you explain why it would be dysarthria and NOT apahsia???


Quote:
Originally Posted by Hitman View Post
Qs 27 ans renal infarction is correct as a pale area on the border of the kidney plus history of hemiplegia ..... F is correct .....
read my explanation in my previous post. I see your point, but then I also see multiple ring legions where the papilla are missing throughout the cortex.


Quote:
Originally Posted by Hitman View Post
Qs 43 ans is D i feel , because the Qs has a hint saying normal transient finding in up to 50% newborns so it is not completely normal so you cannot say it normal , but still take a cardiac consultation ...

so you should tell the patient what excatly they have told us in the stem and check again after 24 most suitable ans ........
I was also thinking D since its a normal finding in 50% of babies. Wait 24 hours to see if it goes away and if it doesn't then get Cardio consult.

What is it the murmur, PDA????


Quote:
Originally Posted by Hitman View Post
please could you explain Qs 10 , 25 , 39 , 49 .......
10. Warts due to HPV. They will cause thickened stratum corneum and epidermis and koilocytic atypia (vacuolated cells)

25. Parathyroid uses the receptor to detect Ca levels in blood. If it is permanently activated parathyroid always thinks Ca levels are normal/high so it will decrease PTH. Decreased PTH means low serum Ca (hypocalcemia). In the kidney since the receptor is activated it will fool itself in thinking it is absorbing Ca when it really isn't. Hence very low reabsorption of Ca and more in the urine.

39. This one I don't know. maybe changing the structure causes the enzyme that breaks it down to not recognize it. Jinni can clarify this.

49. No Ca gradient means that CA is at equilibrium, equal inside and outside. The normal gradient is high outside and low inside. When the Na/K ATPase pumps fail in turn they stop the Na/Ca pump and Ca cannot be pumped out so it increases inside the cell. This is the irreversible stage of cell damage and means the cell is dying or already dead.
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  #6  
Old 02-17-2012
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For 21 Hitman has explained well

Now next Typical diagram for renal papillary necrosis is

http://library.med.utah.edu/WebPath/.../RENAL172.html see the papillary area which is necrosed the image in our question is completely different it has haemorrhagic infarct.
By history and image its Infarct i think

33. Ok osteoblast is correct.

43. I am sure a murmur at the apex is not PDA.Will go with Hitmans explanation for this one.
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Haga excellent explanation for these questions.

For Q 39. What i figured out that endogenous protease prefer L- configuiration rather than D configuiration of AA for degradation. In our body the predominant form is L form so i think this answer is correct.

Here is a link not exactly pertaining to this topic but can give you a link

http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2871709/
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  #8  
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ok , first you ruled out that upperlimb is not involved so the B is pretty incorrect , not think of the lesion as if you are seeing it from the side laterally you will notice that its almost involving the temporal lobe so here its misses the brocas area inferior part of frontal lobe and wernickes which is posterior to the lesion when you see it laterally ..... so it does miss both the areas .......

so by both ways its E .....

that image definitely has a infarct a wedge shaped pale area ... theres no doubt about it plus the history confirms thromboembolic disorder there no history to suggest papillary necrosis they have not mentioned HTN either so its infarct .......

i dont know which murmur it is , the Qs is just made up for a ethical topic ...

Jinni ....... yes that does explain the amino acid thing ...... thanks ..
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  #9  
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well I guess we figured all those out.

As for 43 I'm pretty sure the answer is E now.

You have to offer a cardio consult and then let the parents decide. After all when it comes to decision making you have to leave it in the patients hand.
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Old 03-05-2012
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Can someone help me with Question Number 2! :S
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Old 04-18-2012
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Q34-isnt ACEI contraindicated in renal artery stenosis?
q40- arent they asking about the changes in RBC??
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