USMLE Step 1 - deep truths on pathology
deep truths on pathology
bingousmle - 11-22-08 13:45
a female is positive for occult blood in stool. on further evaluation a friablemass is seen in the ascending colon. which turns out to be an adenocarcinoma according to you pathologist friend. you tell him that immunoperoxidase stain for vimentin would be positive. but he disagrees and says that a mutated gene might have resulted in the condition.
so why are you not justified and what gene is your friend talking about?
bingousmle - 11-22-08 13:45
a female is positive for occult blood in stool. on further evaluation a friablemass is seen in the ascending colon. which turns out to be an adenocarcinoma according to you pathologist friend. you tell him that immunoperoxidase stain for vimentin would be positive. but he disagrees and says that a mutated gene might have resulted in the condition.
so why are you not justified and what gene is your friend talking about?
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#1
Re: deep truths on pathology usmlefever3 - 11-22-08 14:40 vimentin is for connective tissue and cytokeratin for epithelial cells as the pathologist report is adenocarcinoma , the immunochemical stain should be cytokeratin as adenocarcinoma develops from glandular epithelium
the gene is APC which is tumour supressor gene which got mutated to give heriditary non polyposis coli
#2
Re: deep truths on pathology
bingousmle - 11-23-08 00:13 yeah thats true. vimentin is a marker for connective tissue malignancy, whereas cytokeratin would be positive in carcinomas by the immunoperoxidase reaction.
but how did you conclude that it was a case of hereditary non polyposis coli?
#3
Re: deep truths on pathology usmlefever3 - 11-23-08 13:37 i just made a guess for mutated gene causing cancer causing adenocarcinoma of colon .....waiting for ur answer
#5
Re: deep truths on pathology usmlefever3 - 11-26-08 04:56 you may be right as k ras protooncogene is reponsible for colon CA.......someone else might help with better explanation
#6
Re: deep truths on pathology bingousmle - 12-04-08 07:52 The flow of calcium into the cell is an important component of the
upstroke phase of action potentials in which of the following?
a. Cardiac ventricular muscle
b. Intestinal smooth muscle
c. Skeletal muscle fibers
d. Nerve cell bodies
e. Presynaptic nerve terminals
#7
Re: deep truths on pathology kingofhearts - 12-04-08 09:42 e. presynaptic nerve terminals .........
#8
Re: deep truths on pathology bingousmle - 12-04-08 12:10 in a presynaptic nerve terminal calcium is responsible for the fusion of the vesicle but it has no role in action potential...its mainly sodium which is responsible for upstroke phase, so e. is not the correct answer. wanna give another try...
#9
Re: deep truths on pathology zoah2005 - 12-05-08 07:08 i think its A plz give the answer with proper explanation
#10
Re: deep truths on pathology bingousmle - 12-05-08 08:11 in cardiac ventricular muscle Ca is responsible for the plateau phase and Na is responsible for the upstroke...
the answer is intestinal smooth muscle
#11
Re: deep truths on pathology usmlefever3 - 12-05-08 09:12 what are the happens in conducting fibres in heart?.........is there sodium upstroke?
#12
Re: deep truths on pathology bingousmle - 12-05-08 09:29 i think there is a slow channel i.e a calcium spike during the phase 0 in the conducting fibres in the heart , isnt it? waiting for the answer...
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