Thanks for all of the help with DIC, just one more question left...

[nrsbrandy22]

OK.... So a big thank you to those of you that gave me such great responses to my DIC question... Muchas Gracias!

I do however have one last burning question left that I have spent hours and hours researching.... I keep getting conflicting answers, so any input is greatly appreciated.

The question states:

Which of the following statements concerning the actions of the fibrolytic system is NOT correct?

A. The cleavage of fibrin (in clot) and fibrinogen (in plasma) into fibrin degradation (split) products (FDP or FSP) by plasmin is the final reaction.

B. The conversion of plasminogen to plasmin is catalyzed by tissue plasminogen activator, streptokinase, urokinase, and factor XIIa.

C. The fibrinolytic system is activated whenever fibrin is deposited.

D. This system is a part of the intristic coagulation pathway.


So if you had to pick one of these as a WRONG/INCORRECT ANSWER, which would it be??

I think that C is the correct answer, but I am not 100% sure...

THANKS to whoever is kind enough to help me

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[b&ierstiefel]

Gosh, I haven't thought about this in many years (it was 6 years ago when I was an M1 and was trudging through the molecular mechanisms behind coagulation and fibrinolysis)

Normally I would consult a text but I'm not at home right now...I shall do my best to help out anyway...plus, I have colleagues here in the path forum who will correct me if I'm wrong.

Gut feeling...I'm sure A and B are correct statements. I think plasmin can cleave both fibrin and fibrinogen in vitro; however, plasmin-mediated cleavage of fibrin is physiologically the more relevant reaction. Anyways, that makes A one of the correct statements and hence not the answer. As for choice B, it is true that tPA, streptokinase, and urokinase do activate plasminogen to plasmin. I'm not certain about factor XIIa; however, I think the intrinsic pathway can be related to the activation of plasminogen. And factor XII is part of the intrinsic pathway. So I would cross off B and D.

That leaves C as my educated guess. Plus, C has the word "whenever" in it. I usually am wary of answers that contain absolute words such as "whenever", "always", or "never".

Anyways I agree with your answer. What do other ppl think?

 

[nrsbrandy22]

Gosh, I haven't thought about this in many years (it was 6 years ago when I was an M1 and was trudging through the molecular mechanisms behind coagulation and fibrinolysis)

Normally I would consult a text but I'm not at home right now...I shall do my best to help out anyway...plus, I have colleagues here in the path forum who will correct me if I'm wrong.

Gut feeling...I'm sure A and B are correct statements. I think plasmin can cleave both fibrin and fibrinogen in vitro; however, plasmin-mediated cleavage of fibrin is physiologically the more relevant reaction. Anyways, that makes A one of the correct statements and hence not the answer. As for choice B, it is true that tPA, streptokinase, and urokinase do activate plasminogen to plasmin. I'm not certain about factor XIIa; however, I think the intrinsic pathway can be related to the activation of plasminogen. And factor XII is part of the intrinsic pathway. So I would cross off B and D.

That leaves C as my educated guess. Plus, C has the word "whenever" in it. I usually am wary of answers that contain absolute words such as "whenever", "always", or "never".

Anyways I agree with your answer. What do other ppl think?

Thanks for reassuring me.... YOU ARE THE BEST....... So far no one else has replied But thanks for trying to help me

 

[b&ierstiefel]

Thanks for reassuring me.... YOU ARE THE BEST....... So far no one else has replied But thanks for trying to help me

Give it time...you posted your question when most are sleeping. You just happened to catch me when I'm working in Dracula mode .

Cheers.

 

[baoflex]

It seems to me that the answer is D. If memory serves the coagulation cascade and fibrinolytic system are separate but connected. The intrinsic coagulation pathway is the arm of that is initiated by surface contact and factor XII (Hageman factor). Andy is right in that factor XII does cleave plasminogen to plasmin, would this not be the unactivated version of factor XII which is in regions around the clot?

 

[DrBloodmoney]

Yeah I would lean towards D too.

Fibrinogen to Fibrin etc is definetly common pathway.

But XIIa is intrinsic...

tough question

 

[b&ierstiefel]

C and D was in retrospect a tossup. If I just simply read the answer choices at face value, I admit I was wrong and D is the answer. Perhaps I read way too much into questions...that's what f'd me up during 3rd year shelf exams prolly. Nah, I'm just a ***** when it comes down to clinical medicine.

 

[baoflex]

Dr. Robbins says that factor XIIa (activated hageman factor) converts plasminogen to plasmin. I guess that little hypothesis was wrong. I still say D based on the difference between thrombolytic and coagulation pathways.

By the way, I am studying this for a path exam on monday--the path forum was suppose to be a divergence from studying, but instead the coagulation pathway just keeps sucking me back in!!

 

[deschutes]

D would be my choice - same reason: that thrombolysis and coagulation are different processes though related.

 

[garfield]

Dr. Robbins says that factor XIIa (activated hageman factor) converts plasminogen to plasmin. I guess that little hypothesis was wrong. I still say D based on the difference between thrombolytic and coagulation pathways.

By the way, I am studying this for a path exam on monday--the path forum was suppose to be a divergence from studying, but instead the coagulation pathway just keeps sucking me back in!!

Dr. Robbins (if you're talking about the guy who whose name is on THE path book of all med students) isn't talking too much anymore... he's dead.

 

[Willie B]

My vote is for D also for reasons already noted ( ie Coagulation and Fibrinolysis are two different pathways.)

 

[baoflex]

Dr. Robbins (if you're talking about the guy who whose name is on THE path book of all med students) isn't talking too much anymore... he's dead.

would you prefer I say kumar?

 

[garfield]

would you prefer I say kumar?

Sure, why not? Was just messin' with ya.