26malik
Forum Guru
Topics: 39
Posts: 429
|
A 54-year-old diabetic patient reports to his physician's office complaining of an unresolved skin lesion on his foot. The 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 a 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
K. Toxic shock syndrome toxin-1
___________________
There is always hope
|
| vallia
Forum Guru
Topics: 98
Posts: 889
|
A
___________________
fight possessed
|
| tolito
Forum Fanatic
Topics: 119
Posts: 2,164
|
A
___________________
It has been a looooong hard journey but I am inches away from my destination...
|
| zaidsuror
Forum Elite
Topics: 61
Posts: 238
|
why A?
What is the diagnosis?
___________________
footsteps on the sands of time are not made by sitting around.
|
| 26malik
Forum Guru
Topics: 39
Posts: 429
|
The correct answer is E.
This 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 its target cells are heart and nerve.
Anthrax toxin (choice A) is an adenylate cyclase that causes fluid loss from cells.
Botulinum toxin (choice B) is a neurotoxin that decreases acetylcholine synthesis.
Cholera toxin (choice C) acts to increase adenylate cyclase activity by ribosylation of GTP-binding protein.
Clostridium perfringens alpha toxin (choice D) is a lecithinase.
Escherichia coli labile toxin (choice F) works in a fashion similar to the cholera toxin.
Pertussis toxin (choice G) causes fluid loss by ribosylating Gi.
Shigatoxin (choice H) decreases protein synthesis by inhibiting the 60S ribosomal subunit.
Streptococcal erythrogenic toxins (choice I) act similarly to the diphtheria toxin, but do so by increasing cytokine production.
Tetanus toxin (choice J) is a neurotoxin that inhibits the inhibitory neurotransmitters glycine and GABA.
TSST-1 (choice K) is a superantigen that acts by increasing cytokine production and decreasing liver clearance of endotoxin.
Edited by 26malik on 04/17/06 - 06:47 AM
___________________
There is always hope
|
| zaidsuror
Forum Elite
Topics: 61
Posts: 238
|
I knew it was ,that's why i dot confused with all answering with a.
___________________
footsteps on the sands of time are not made by sitting around.
|
| vallia
Forum Guru
Topics: 98
Posts: 889
|
yes I misunderstood the Q
___________________
fight possessed
|
| pocas
Forum Elite
Topics: 7
Posts: 169
|
A
|
| r_albayunen
Forum Senior
Topics: 0
Posts: 218
|
jejej i got confused also in q bank ..
|
| tolito
Forum Fanatic
Topics: 119
Posts: 2,164
|
i thought it was an anthrax lesion!!! i will go check up on the necrotic mass from anthrax and see the difff from this one.
thanks. good question
___________________
It has been a looooong hard journey but I am inches away from my destination...
|
|
| |
| | | | | | | | | | |
