Platelets (adhesion and aggregation)ocw.usu.ac.id/course/download/1110000096-hematology-and-immunology... · • Hess test (commonly used): pressure isHess test (commonly used): pressure

HAEMOSTASIS(VIRCHOW’S TRIAD)(VIRCHOW’S TRIAD)

Blood vessel (vasoconstriction)Blood vessel (vasoconstriction)Platelets (adhesion and aggregation)

C l ti d Fib i l iCoagulation and Fibrinolysis

Prof. Dr. Herman Hariman, Ph.D (U.K), SpPK (KH)Prof. Dr. Adi Koesoema Aman, SpPK (KH)

HAEMORRHAGICHAEMORRHAGIC SCREENING TEST

A Global test that may predict what happened with thepp

Blood vessel (vasoconstriction)( )Platelets (adhesion and aggregation)

Coagulation and FibrinolysisCoagulation and Fibrinolysis

BLOOD VESSELBLOOD VESSEL

BLOOD VESSELSMEASUREMENT

TORNIQUET TESTBLEEDING TIMEBLEEDING TIME

Tourniquet TestC ill f iliCapillary-fragility-test

• Hess test (commonly used): pressure isHess test (commonly used): pressure is put midway between systole and diastole for 5 minutes Reading is done 5 minutesfor 5 minutes. Reading is done 5 minutes after the release of the cuff

• Rumple Leed (X): the same pressure as• Rumple Leed (X): the same pressure as above but for 15 minutes and reading is done straight away after the release of thedone straight away after the release of the cuff

Pressure midway between systole and diastoleFor 5 minutes (Hess test)o 5 u es ( ess es )

InterpretationInterpretation

• (+): small red dots difficult to be seen(+): small red dots difficult to be seen• (++): bigger dots and easily seen

( ) t l il b t l it• (+++): not only easily seen but also quite prominent and sometimes confluent

• (++++): true bruising

Bleeding TimeBleeding Time

• As a global test to measure roughlyAs a global test to measure roughly• Platelet’s function

Pl t l t’ b• Platelet’s number

Put blood pressure at 40 mmHg

First blood drop is wipedN t bl d i ti d ff b filt 30Next, blood is tipped off by filter paper every 30 sec

Normal is less than 5 min

PLATELETPLATELET

NUMBER (USUALLY SEVERE)

PLATELET

FUNCTION (LESS SEVERE)

Bleeding TimeBleeding Time

• As a global test to measure roughlyAs a global test to measure roughly• Platelet’s function

Pl t l t’ b• Platelet’s number

PLATELET NUMBER IS MEASURED FROM FULL BLOOD COUNT

CELL COUNTER

PLATELET FUNCTION IS TESTED USING PLATELET AGGREGOMETER

PLATELETSPLATELETS

PLATELET ADHESION PLATELET AGGREGATIONPLATELET AGGREGATION

Platelet Aggregation● Platelet adhesion is mediated by vWF. This activates platelets

causing release of TxA2

● During activation, a receptor for fibrinogen becomes exposed onthe platelet membrane.

●Activated platelets release by ADP, Epinephrin, serotonin:

Fibrinogen ADP/ATPvWF Serotonin dense core granulesvWF SerotoninFactor V Ca2+

Factor VIIIPl t l t d i d th f t (PDGF) t h liα

-gra

nule

s dense core granules

Platelet derived growth factor (PDGF) ~ promotes healingPlatelet factor IV – prevents formation of active thrombin

inhibitor from heparin and anti-thrombin III.

α

AGGREGATION OF PLATELETAGGREGATION OF PLATELET

IS MEASURED AFTER ADDING

THE PLATELET AGONISTS

SUH AS

ATPEPINEPHRINSEROTONINRISTOCETIN

Graph seen in the platelet aggregometer after adding of some agonists

Basic Principle ofpvon Willebrand’s Factor Test

• FUNCTIONAL TEST• Ristocetin co-factor assay dg Plt aggregometer

• ANTIGEN TEST (immunoassay)• Radioimmunoassay (RIA)• Enzyme-linked immunoassay (ELISA)

Basic Principle ofBasic Principle ofFibrinogen test

• Among other coagulation factors, Fibrinogen has no enzymatic activity and hence there is no functional test but only detection of protein

Intrinsic pathway

XIIa

TF

Extrinsic PathwayXIa

ProthrombinVIIa

TF

IXa

XaVa

VIIIaV

VIII

Fibrinogen FibrinThrombin Soft clot

gXIIIa

FibrinHard clot

FIBRINOGEN ASSAYSFIBRINOGEN ASSAYS

• Radial immunodifussionRadial immunodifussion• Clauss method (pure clotting-based)• Blomback and Blomback (+thrombin –Ca++)Blomback and Blomback (+thrombin Ca++)

soluble and unstabilized. The tyrosine content is measured after adding urea.g

• Ratnoff and Menzies: Fibrinogen is clotted into Fibrin in glass beads, washed and bolied +NaOH, tyrosine measured with Fiolin Calcateu-Phenol reagent

COAGULATION AND FIBRINOLYSIS

I t i i th E t i i thIntrinsic pathway Extrinsic pathway

Final Common pathwayFinal Common pathwayX, V,

Prothrombin Thrombin

Fibrinogen Fibrin

I t i i th E t i i thIntrinsic pathway Extrinsic pathway

Final Common pathwayFinal Common pathwayX, V,

Prothrombin Thrombin

Fibrinogen Fibrin

Prothrombin Time (PT)

I t i i th E t i i thIntrinsic pathway Extrinsic pathway

Final Common pathwayFinal Common pathwayX, V,

Prothrombin Thrombin

Fibrinogen Fibrin

Activated Partial Thromboplastin Time (APTT)

I t i i th E t i i thIntrinsic pathway Extrinsic pathway

Final Common pathwayFinal Common pathwayX, V,

Prothrombin Thrombin

Fibrinogen Fibrin

Thrombin Time (T.T)

BASIC HAEMORRHAGIC SCREENING TEST

MEASURES ROUGHLYMEASURES ROUGHLY• Full Blood Count• Torniquet test• Bleeding timeBleeding time• Prothrombin time

A ti t d ti l th b l ti ti• Activated partial thromboplastin time• Thrombin time

To give a rough idea of what happened in disturbedhappened in disturbed

HAEMOSTASIS

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