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painful ,erosive ,expanding sore


painful ,erosive ,expanding sore


حالة سريرية

الوصف الكامل Background
A 54 year old diabetics patient reports to his physician's office complaining of an unresolved skin lesion on his foot .This lesion began several weeks ago as a blister
and has since become a painful ,erosive ,expanding sore.On examination,the affected site is now 5 cm in diameter with black necrotic center and raised red edges.which of the following toxins has a mechanism of action most similar to the toxin responsible for tissue damage in this patient??

a-Anthrax toxin
b-botulinum toxin
c-cholera toxin
d-clostridium perfringens alpha toxin
e-diphtheria toxin
f-Escherichia coli labile toxin
g-Pertussis toxin
h-shigatoxin
i-streptococcal erythrogenic toxins
j-tetanus toxin

mbs2380's picture
by
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d

qusei

try another time,it is really a tricky q ,...
the organism responsible for this case is not mentioned here,but the q is about the organism whose toxin has a similar mechanism of action......

Hint:the mechanism of action here is :Inhibition of the protein synthesis by acting on elongation factor2 ....

mbs2380's picture
mbs2380
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So we can make the answer like that:
which of the following toxins inhibits protein synthesis by acting on elongation factor2
mbs2380's picture
mbs2380
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-skin lesion on foot of diabetic patient ... i will think of pseudomonas aurogenus ( sorry if there is misspelling )

- black necrotic center is an aerobic enviroment for this bug

the mechanism of action of its toxin via EF
and another bacteria which has similar mechanism is diphtheria ( choice e )

dr.msh's picture
dr.msh
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Quote:
-skin lesion on foot of diabetic patient ... i will think of pseudomonas aurogenus ( sorry if there is misspelling )

- black necrotic center is an aerobic enviroment for this bug

the mechanism of action of its toxin via EF
and another bacteria which has similar mechanism is diphtheria ( choice e

good job man

mbs2380's picture
mbs2380
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The correct answer is E :the patient's wound is infected with pseudomonas aeruginosa ,and the characteristic lesion described is called ecthyma gangrenosum. The pseudomonas alpha toxin,which is responsible for the tissue damage ,inhibits protein synthesis by acting on EF-2 with a primary target cell in the liver.The diphtheria toxin has a similar action ,although the target cells are
heart and nerve.

Anthrax toxin (choiceA) is an adenylate cyclase that causes fluid loss from cells.

Botulinum toxin (choiceB) is a neurotoxin that decreasesx acetylcholine synthesis

Cholera toxin (xhoice C) acts to increase adenyl cyclase activity by ribosylation of GTP-binding protein.

Clostridium perfringens alpha toxin (choice D) is a lecithinase.

Escerichia coli labile toxin (choice F) works in a fashion similar to the cholera toxin.

Pertussis(choice G) causes fluid loss by ribosylating Gi.

Shigatoxin (choice H) decreases protein synthesis by inhibiting 60S ribosoma subunit.

Streptococcal erythrogenic toxins (choice I) act similary to the diphtheria toxin,but doso by increasing cytokine production.

Tetanus toxin(choice J) is a neurotoxin in that inhibits the inhibitory neurotransmiter glycin and GABA.

mbs2380's picture
mbs2380
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Embarrased
يا الله عم نتعلم Razz

qusei

Quote:
يا الله عم نتعلم

عنجدّ عم نتعلم Shocked Shocked Shocked
Eye-wink Eye-wink Eye-wink

quu's picture
quu
السنة السادسة


و لا يهمك قصي ... لو مالي قاري micro ما كنت عرفت الجواب لهيك سؤال basic !

و نصيحة لطلاب السنوات الأولى لا توهمو حالكم و تفكرو انو السؤال فوق مستواكم إذا ما عرفتو تجاوبو عليه ... إذا عندك فكرة مسبقة عن الموضوع و بشكل موجه بتجاوب ... أما إذا مالك قاريه فغلط تقارن حالك بغيرك بشكل يسبب لك الاحباط ... و بيعجبني mbs لانو عم يشتغل صح من بداية الطريق !

dr.msh's picture
dr.msh
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Quote:
بيعجبني mbs لانو عم يشتغل صح من بداية الطريق !

ما شاء الله عنجد ادامو مستقبل كتير مشرق Razz

qusei


thank u for passing by

mbs2380's picture
mbs2380
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Now if we look at the discription of the skin lesion in this case ,we can conclude that it looks like the lesion made by anthrax toxin ,I mean:
black necrotic center and raised red edges
the thing that confused me.....

but there is one big different between them:
that which is produced by anthrax toxin is painless,,on other hand ,the lesion which is produced by pseudomonas is painful

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mbs2380
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