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Perf Tech 3 > 13. Platelet Gel- Exam 3 > Flashcards

13. Platelet Gel- Exam 3 Flashcards

1
Q

Young, fecund, robust, inactivated platelets are what size

A

1-3 μm discoids

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2
Q

platelet concentration and life span

A

Humans: Normally ~ 150,000-300,000/ml of blood

Life span~one week

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3
Q

what do α-granules contain

A

clotting factors, growth factors, and various other proteins

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4
Q

what do Dense granules contain

A

ADP, ATP, Serotonin, and Calcium

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5
Q

young VS old platelets [weight/size]

A

Young platelets are large and heavy (dense)

Old platelets are small and light

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6
Q

Young large platelets aggregate how much faster than older platelets

A

3-5 x

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7
Q

Young platelets release how much more ATP and ADP than do older platelets

A

ATP (4-8 x)

ADP (4-6 x)

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8
Q

Old platelets require substantially greater amounts of ____ to be activated than do young platelets

A

ADP

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9
Q

What are the 7 steps platelets go through- starting with the wound and ending with platelet aggregation

A
  1. Wound
  2. Exposes subendothelial collagen
  3. Binds von Willebrand Factor
  4. Platelet adhesion to blood vessel wall via GP IIb/IIIa
  5. Platelet activation
  6. Platelet cytoskeleton (via actin and myosin) expands
    from a disc to a multi-pseudopodal sticky blob
  7. Platelet aggregation
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10
Q

why do aggregated platelets release serotonin

A

Vasoconstriction

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11
Q

why do aggregated platelets release ADP

A

Recruits other platelets to aggregate and degranulate

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12
Q

why do aggregated platelets release thromboxane

A

Platelet aggregation and PGF release

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13
Q

PDGF: Platelet-Derived Growth Factor=

A

STRONGLY mitogenic and chemotactic for leukocytes
-By itself PDGF application doubles the rate of collagen
deposition in a wound

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14
Q

TGF-β: Transforming Growth Factor-Beta=

A

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

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15
Q

Attracted neutrophils and macrophages release what?

A

a host of other healing factors

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16
Q

Cells expressing the CD34 protein are concentrated where?

A

in the mononuclear layer of platelet concentrate

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17
Q

Cells expressing the CD34 protein are what?

A

stem cell “markers” and are important for other cells’ adhesion/chemotaxis

18
Q

Platelet Rich Plasma (PRP)=

A

“The components of whole blood remaining after the removal of (most of) the red cells”

  • The buffy coat (white cells and platelets) extending ??? into the top of the red cell column
  • PLUS all of the plasma
19
Q

Platelet Poor Plasma (PPP)=

A

“Plasma layer without the buffy coat”

-So…you get lots of fibrinogen & coagulation factors but no cells

20
Q

Platelet concentrate: Buffy coat =

A

leukocytes + platelets

21
Q

Platelet concentrate: Leukocyte=

A

neutrophils, eosinophils, basophils, macrophages, B- and T-lymphocytes

22
Q

Platelet Gel (PG)=

A

Platelet Concentrate with enough fibrinogen (2-4mg/ml) to “set up” when combined with an activator
-Platelets 2-6x over baseline

23
Q

Platelet Gel ‘activator’

A

“Activator” = Thrombin (bovine or human), Calcium (usually CaCl₂) or Collagen

24
Q

How many platelets do you need:

Theory 1) Increase in multiples above baseline

A
  • Typically 2-6 times above baseline
  • Evidence suggests >6x actually delays healing…why?
  • Theory suggests possible up-regulation of other tissues to “factors” in the presence of thrombocytopenia
25
Q

How many platelets do you need:

Theory 2) Absolute numeric concentration

A

-Typically > 1,000,000/μL

26
Q

Evidence supports platelet gel use in promoting healing in virtually all tissues except?

A

nervous tissue

27
Q

what are some platelet gel contraindications

A
  • Severe hypovolemia
  • Unstable angina/LM disease
  • Heparin therapy
  • Post-incisional harvest
  • Thrombocytopenia (~
28
Q

what should you never apply platelet gel to

A

coronary grafts

29
Q

To get more volume…what has to happen

A

you either need more blood initally
lower “Increases Above Baseline
you add more RBCs to the mix

30
Q

To get more volume…what has to happen

A

you either need more blood initally
lower “Increases Above Baseline
you add more RBCs to the mix

31
Q

How many platelets in a “unit” of whole blood?

[formula]

A

(Platelets/μL) X 1000 X (ml of whole blood)

32
Q

How many platelets in a “unit” of PRP?

[formula]

A

(Platelets/μL) X 1000 X (ml of PRP)

33
Q

What is the percent yield of platelets in PRP?

[formula]

A

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

34
Q

Essentially two “fields” of stem cell therapy are?

A

1) Bone Marrow (“Mesenchymal”) Derived

2) Adipose Derived

35
Q

Mesenchymal stem cells are generally found in?

A

bone marrow but can be isolated from circulating blood, cord blood, fallopian tubes, and fetal tissue.

36
Q

Mesenchymal stem cells have a High capacity for?

A

High capacity for pluropotentiality

High capacity for self renewal

37
Q

problems with Mesenchymal stem cells

A

Stem cells are “few and far between” in the bone marrow

38
Q

adipose derived stem cells=

A

> 500 X more stem cells in 1 gram of fat as compared to 1 gram of aspirated bone marrow
–Can be extracted without anesthesia/sedative/tranquilizer

39
Q

which is better? Mesenchymal or adipose?

A

Technology for utilizing adipose-derived stem cells is much simpler (and more commercially available)
(Moving away from B.M. towards A.D.)

40
Q

Stem cells have the ability to “morph”…And they are synergistically attracted/stimulated by what?

A

activated platelets and the “factors” those platelets produce

41
Q

adipose stem cell extraction systems do what 4 things

A

1) Remove the “lipids”
2) Remove the supernatant
3) Concentrate the adipose stem cells
4) Maintain the Stromal Vascular Fraction (SVF) which creates a warm, fuzzy microenvironment for the stem cells and helps promote graft retention
5) +/or allow for the stem cell extract to be mixed at some ratio with platelet concentrate in an aerobic environment

42
Q

what is the estimated platelet/adipose ratio

A

1:2-1:10

Perf Tech 3 (15 decks)

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