Wendt - AntiCoag Flashcards
role of plasmin?
degrades fibrin – and dissolves clot
all thromboembolytics work to increase the conversion of ______ to ______?
plasminogen; plasmin
What activates plasminogen to plasmin
t-PA
t-PA cleaves a ______ bond to activate plasmin
arg-val bond
Thrombolytics:
______ cleaves a arg-val bond to activate plasmin
t-PA
t-PA is inhibited by what things?
PAI-1 and PAI-2
plasmin is a ________ that digests fibrin and fibrinogen
proteolytic enzyme
Plasminogen is an anticoagulant protein that circulates in _______ form and is deposited on to a growing clot.
inactive
t-PA is known as a _______ protease
serine
plasmin is inactivated by _________
a2-antiplasmin
indications for thrombolytic therapy:
acute or chronic?
acute!
indications for thrombolytic therapy:
3 things
- acute MI
- acute ischemic thrombotic stroke
- PE
what are the 5 options of thrombolytic drugs
- Alteplase
- Reteplase
- Tenecteplase
- Streptokinase
- Urokinase
which thrombolytic drugs are known to be recombinant t-PA drugs
- Alteplase
- Reteplase
- Tenecteplase
Thrombolytic drug:
Streptokinase makes a complex with _______
plasminogen
Thrombolytic drug:
Streptokinase promotes ________ by the _________ molecule
promotes plasminogen activation; by adjacent plasminogen molecule
T or F: Streptokinase has intrinsic enzyme activity
FALSE! it does not directly degrade clots — it makes a complex that catalyzes conversion of inactive plasminogen to active plasmin
Anti-Fibrolytic Agents are?
- Lysine
- Tranexamic acid
- Aminocaproic acid (EACA)
plasmin binds to fibrin through a ______ binding site to activate fibrinolysis
lysine
anti-fibrinolytic agents are used to stop _____ caused by _______ drugs
stop bleeding; caused by thrombolytic drugs
how does plasminogen get converted to plasmin?
t-PA
how does Alteplase work?
its a thrombolytic drug that is a recombiant human t-PA
binds to fibrin
how does Reteplase work?
recombinant human t-PA
LESS FIBRIN specific/lacks fibrin binding domain
is Reteplase more or less fibrin specific than Alteplase?
less fibrin specific
is Tenecteplase more or less fibrin specific than Alteplase?
more specific!
Tenecteplase:
short or long 1/2 life?
long
-plase thrombolytic drug lacks fibrin binding domain
Reteplase
t-PA binds to _____ and activates bound ________ 100x more rapidly than in circulation
fibrin; plasminogen
Mutations in Tenecteplase lead to:
______ half life
reduce __________
enhance activity at ______
LONGER half life;
reduce INHIBITION by PAI
enhance activity at THROMBI
______ drug is a recombinant t-PA with the 527 aa residue
Altelplase
_______ drug is a recombinant t-PA with the 527 aa residue deletion
Reteplase
Anti-fibrinolytic agents act as a ________ to bind to the receptor on plasminogen and plasmin - leads to a ______ of plasmin binding to target fibrin
lysine analog; blockade
is Tranexamic Acid or Aminocaproic Acid (EACA) more potent as being a anti-fibrinolytic agent
Tranexamic Agent
do platelets have a nucleus?
no
are platelets made of granules?
yes
do platelets have organelles?
yes (but no nucleus)
Thrombus Formation is also known as what?
platelet plug or white thrombus
3 main steps for Thrombus formation are…
1 - platelet adhesion/Shape change
2 - platelet secretion
3 - Platelet aggregation
Thrombus Formation: STEP 1
Adhesion is mediated by what 2 things binding
GP1a; GP1b
GP 1a binds to ________
GP1b binds to _______
1a - collagen
1b - von willebrand factor (bridged to collagen)
Platelet adhesion mediated by:
_____ binding to collagen
_____ binding to VonWillebrand Factor (bridged to collagen)
________ facilitates receptor binding
GP1a
GP1b
Shape change
platelet adhesion:
intact ______ cells secret _____ to inhibit thrombogenesis
intact ENDOTHELIAL; secret PGI2 (prostacyclin)
Platelet secretion:
Platelet granules release what 3 things?
- ADP
- TXA2 (thromboxane A2)
- 5-HT (serotonin)
ADP, 5-HT, TXA2 activate and recruit what
other platelets
Platelet Aggregation:
ADP/5-HT/TXA2 activate/induce conformation of ______ receptors to bind _____
GP11b/111a receptors
bind fibrinogen
Platelets get cross linked by ______
fibrinogen
_____ is used to stabilize and anchor aggregated platelets
Fibrin
Platelet Activation:
1) _______ injury
2) exposed ______
3) Platelet ______
4) platelet _______
5) ______ activation
6) Platelet ______
7) Platelet ______
vascular injury exposed collagen adhesion activation integrin activation aggregation plug
what are the 5 options for Antiplatelet drugs
COX1 inhibitors ADP receptor inhibitors blockers of GP11b/111a receptors PDE3 inhibitors Protease Activated Receptor inhibitors
what drug is a COX 1 inhibitor
Aspirin
Aspirin (ASA):
inhibits platelet COX1 by ______
acetylation
Aspirin (ASA):
Blocks the conversion of ___ to ___
AA to PGG2
Aspirin (ASA):
Interferes with platelet ______
aggregation
Aspirin (ASA):
Prolongs _____ time
bleeding
Aspirin (ASA):
Prevents ________ formation
aterial thrombi
Aspirin (ASA):
Inhibition of _______ in platelets is the key to anti-platelet activity of ASA
TXA2 synthesis
Aspirin (ASA):
(reversible or irreversible) inhibition by acetylation of COX1
IRREVERSIBLE;
Aspirin (ASA):
end up having permanent loss of platelet cox1 activity bc of decreased ______
TXA2
Aspirin (ASA):
Irreversible inhibition by acetylation of _____
COX1
Aspirin (ASA):
(reversible or irreversible) inhibition by ________ of COX1
acetylation
at higher doses of aspirin, _______ production in tissue is inhibited
prostacyclin
T or F: aspirin increases PT time
FALSE (aspirin prolongs bleeding time but no PT time…)
is it used in Platelet Adhesion or Platelet Aggregation?
GP1a
platelet adhesion (binds to collagen)
is it used in Platelet Adhesion or Platelet Aggregation?
GP2a
platelet adhesion
is it used in Platelet Adhesion or Platelet Aggregation?
GP11b
platelet aggregation (it is an integrin)
is it used in Platelet Adhesion or Platelet Aggregation?
GP111a
platelet aggregation (it is an integrin)
what are the 2 ADP receptors involved in activating platelets
P2Y1; P2Y12