Platelet Gel- Exam 3 Flashcards Preview

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Flashcards in Platelet Gel- Exam 3 Deck (55):
1

Young, fecund, robust, inactivated platelets are _______ um discoids.

1-3

2

Humans: Normally how many platelets in blood?

150,000-300,000 / ul of blood

3

What is the life span of a platelet?

About a week

4

What do alpha granules contain?

Clotting factors, growth factors, and various other proteins

5

What do dense granules contain?

ADP, ATP, serotonin, calcium

6

How do young and old platelets compare?

Young platelets are large and heavy (dense)
Old platelets are small and light

7

Do young or old platelets aggregate faster? How much faster?

Young large platelets aggregate much faster; about 3-5x faster than older platelets

8

Do young or old platelets release more ATP? ADP?

Young platelets release more ATP (4-8x more)
Young platelets release more ADP (4-6x more)

9

Do young or old platelets require substantially greater amounts of ADP to be activated?

Older platelets require more ADP to be activated

10

What are the 3 phases that occur after tissue injury?

Primary Hemostasis
Secondary Hemostasis
Fibrinolysis

11

Primary Hemostasis

Vasoconstriction
Platelet adhesion
Platelet aggregation

12

Secondary Hemostasis

Activation coagulation factors
Fibrin formation

13

Fibrinolysis

Activation fibrinolytic system
Clot lysis

14

Fibrinolysis

Activation fibrinolytic system
Clot lysis

15

Wound --> Exposes what?

Subendothelial Collagen

16

When subendothelial collagen is exposed, what binds?

von Willebrand Factor

17

After vWF binds, platelet adhesion to blood vessel wall occurs via what?

Glycoprotein IIb/IIIa receptors

18

When platelet adhesion to blood vessel wall occurs, what happens next?

Platelet activation

19

What happens when platelets are activated?

Platelet cytoskeleton (via actin and myosin) expands to form a disc to a multi-pseudopodal sticky blob leading to platelet aggreagation

20

What does serotonin do?

vasoconstriction

21

What does ADP do?

Recruits other platelets to aggregate and degranulate

22

What does thromboxane do?

Platelet aggregation and PGF release

23

PDGF

Platelet Derived Growth Factor

24

What does PDGF do?

Strongly mitogenic and chemotactic for leukocytes
By itself, application doubles the rate of collagen deposition in a wound (plus a bunch of tother stuff that aggressively accelerates healing)

25

TGF-B

Transforming Growth Factor Beta

26

What does TGF-B do?

Also strongly mitogenic
Allows damaged (irradiated, corticosteroid-treated) tissues to revert to normalized collagen deposition

27

What do attracted neutrophils and macrophages release?

A host of other healing factors

28

Are granulocytes (neutrophils) good?

Good/bad/indifferent

29

Where are cells expressing CD34 protein concentrated?

IN the mononuclear layer of platelet concentrate

30

What are CD34 proteins?

Cells are stem cell "markers" and are important for other cells' adhesion/chemotaxis

31

What are CD34 proteins?

Cells are stem cell "markers" and are important for other cells' adhesion/chemotaxis

32

What is the source of TGF-B?

Platelets, extracellular matrix of bone, cartilage matrix, activated TH1 cells and natural killer cells, macrophages/monocytes and neutrophils

33

What does TGF-B do?

Also strongly mitogenic
Allows damaged (irradiated, corticosteroid-treated) tissues to revert to normalized collagen deposition

Mesenchymal cell proliferation
Regulates endothelial, firboblastic and osteoblastic mitogenesis
Regulates collagen syntehsis

34

What is the source of TGF-B?

Platelets, extracellular matrix of bone, cartilage matrix, activated TH1 cells and natural killer cells, macrophages/monocytes and neutrophils

35

What is the source of Basic Fibroblast Growth Factor?

Platelets, macrophages, mesenchymal cells, chondrocytes, osteoblasts

36

PRP

Components of whole blood remaining after the removal of most of the red cells; buffy coat

37

Buffy coat layer

white cells and platelets

38

PPP

plasma layer without the buffy coat; so you get lots of fibrinogen and coagulation factors but no cells

39

Platelet Concentrate

Essentially the buffy coat +/- a small (variable ) amount of plasma
Buffy coat = leukocytes + plts
Leukocytes = neutrophils, eosinophils, basophils, macrophages, B and T lymphocytes

40

Platelet Gel

Platelet concentrate with enough fibrinogen (2-4 mg/ml) to set up when combined with an activator

41

What is the activator in plt gel?

Thrombin (bovine or human)
Clacium (usually ClC2) or collagen
Platelets 2-6x over baseline

42

What are the two theories for how many plts you need?

1. Increase in multiples above baseline (2-6 x baseline)
2. Absolute numeric concentration (Typically > 1,000,000/ul

43

What happens when platelets above 6x baseline?

Delays healing; possible up regulation of other tissues to factors in the presence of thrombocytopenia

44

Platelet gel is used in promoting healing in all tissues except what?

Nervous tissue

45

Platelet Gel Contraindications

Severe hypovolemia
Unstable angine/LM disease
Heparin therapy
Post-incisional harvest
THrombocytopenia (

46

Where should you NEVER apply plt gel?

Coronary grafts

47

How many platelets in a "unit" of whole blood?

(Platelets/ul) x 1000 x (ml of whole blood)

48

How many platelets in a "unit" of PRP?

(Platelets/ul) x 1000 x (ml of PRP)

49

What is the percent yield of platelets in PRP?

(# platelets in PRP x 100) / (#platelets in whole blood)

50

What are the two fields of stem cell therapy?

Bone marrow (mesenchymal) derived
Adipose derived

51

Mesenchymal Stem Cells

Generally found in the bone marrow but can be isolated from circulating blood, cord blood, fallopian tubes, and fetal tissue

High capacity for pluropotentiality
High capacity for self renewal

52

Adipose- Derived Stem Cells

Also a source of multipotential stem cells
>500x more stem cells in 1 gram of fat as compared to 1 gram of bone marrow
Have similar ability to differentiate as does BM derived
Can be extracted without antesthesia/seditive
Avoids fetal stem cell discussion

53

Stem cells are attracted and stimulated by what?

Activated platelets and the "factors" those platelets produce

54

Adipose-Derived Stem Cell Extraction Systems

1. Remove lipids
2. Remove supernatant (saline, phenylephrine, lidocaine)
3. Concentrate the adipose stem cells
4. Maintain stromal vascular fraction (SVF) which creates a wgood microenvirnment to help promote graft retension
5. allow stem cell extract to be mixed asome ratio with platelet concentrate in an aerobic environment

55

SVF

stromal vascular fraction (SVF)