BB Lec M1.2 Flashcards
State three areas of RBC biology that are crucial for normal erythrocyte survival and function
- Normal chemical composition and structure of the RBC membrane
- Hemoglobin structure and function
- RBC metabolism
Give me the components of the RBC Membrane
A semipermeable lipid bilayer supported by a mesh-like protein cytoskeleton structure
MAIN LIPID COMPONENT of the RBC Membrane
Phospholipids
What is the biochemical composition of the RBC membrane
52% protein, 40% lipid, and 8% carbohydrate
RBC life span
120 Days
The biochemical composition of the RBC maintains a critical role in two RBC characteristics. What are these characteristics?
RBC Deformability and RBC Permeability
When there is a loss of membrane deformability, there is a loss of (1) _____ and decrease of (2) _______.
(1) Loss of ATP (Adenine triphosphate)
(2) Decrease of phosphorylation of spectrin
What is spectrin?
A protein that maintains the stability and structure of the cell membrane and the shape of a cell
Accumulation or increase in the deposition of membrane ______ also results in membrane rigidity and loss of pliability.
Calcium
What is the organ that functions in extravascular sequestration?
Spleen
They are in charge of the removal of aged, damaged, or less deformable RBCs or fragments of their membrane. Meaning if the RBC membrane is not deformable, they are at a disadvantage going through smaller blood vessels, which later on damages the RBC, resulting in the removal or sequestration of the spleen.
Loss of the viable red cell membrane results in the formation of these type of abnormal red cells.
Spherocytes and Bite Cells
Note that survival of these cells are shortened
One of the permeability properties of the RBC membrane and the active RBC cation transport prevents is ____
Colloid hemolysis
TRUE OR FALSE:
Any abnormality that increases permeability or alters cationic transport may increase RBC survival.
FALSE
If RBC membrane is more permeable and cationic transports accumulates, RBC storage lesion may form, which shortens RBC survival.
TRUE OR FALSE:
The RBC membrane is freely permeable to water and cations.
FALSE
They are freely permeable to water and ANIONS
Give me 2 example of cations
Sodium (Na+) and Potassium (K+)
What are the two variable being maintained by controlling the intracellular concentrations of sodium and potassium
RBC volume and water homeostasis
What is the erythrocyte intracellular-to-extracellular ratios for Na+?
1:12
What is the erythrocyte intracellular-to-extracellular ratios for K+?
25:1
How many cationic pumps are actively transporting Na+ out of the cell and K+ into the cell, requiring energy in the form of ATP?
300
It is a cytoplasmic calcium-binding protein, and is speculated to control these pumps and to pre-vent excessive intracellular Ca2+ buildup.
Calmodulin
Between Na+ and K+ in a normal case, what cation goes out and in of an RBC?
Na+ (Sodium) should go out of the cell and K+ (Potassium) should go into the cell.
Between Na+ and K+ in an abnormal case, what cation goes out and in of an RBC?
Na+ (Sodium) stays in the cell and K+ (Potassium) stays out of the cell.
Low Affinity to Oxygen
Tensed Form 2,3-DPG
High Affinity to Oxygen
Relaxed Form 2,3-DPG
Why are RBCs’ metabolic pathways are mainly anaerobic?
Due to the following:
- The function of the RBC is to deliver oxygen, not to consume it. -
- Because the mature erythrocyte has no nucleus and there is no mitochondrial apparatus
- For oxidative metabolism, energy must be generated almost
exclusively through the breakdown of glucose.
State the 3 ancillary pathways of the RBC
- Pentose phosphate pathway
- Methemoglobin reductase pathway
- Luebering-Rapoport shunt
Main RBC Metabolism Pathway
Glycolytic Pathway
What is the process of Glycolytic Pathway and explain it.
Glycolysis – Conversion of Glucose to Pyruvate
Glycolysis generate (1) ___ of ATP, while pentose phosphate pathway provides (2) ___ energy.
(1) 90%
(2) 10%
This pathway permits the accumulation of an important RBC organic phosphate, 2,3-diphosphoglycerate
Luebering-Rapoport shunt
The amount of ______ found within RBCs has a significant effect on the affinity of hemoglobin for oxygen and therefore affects how well RBCs function post-transfusion.
2,3-DPG
Primary function of Hemoglobin
Gas transport (O2 to tissues & CO2 excretion)
The unloading of oxygen by hemoglobin is accompanied by widening of a space between (1) _____ and the binding of 2,3-DPG with the formation of (2) ____
(1) β chains
(2) Anionic Salt Bridges
What is the Storage Time if Citrate-phosphate dextrose (CPD) is added? Is it an anticoagulant or additive?
21 Days (Anticoagulant)
Allosteric changes that occur as the hemoglobin loads and unloads oxygen are referred to as the ____
Respiratory Movement
What is the Storage Time if Citrate-phosphate-double-dextrose (CP2D) is added? Is it an anticoagulant or additive?
21 Days (Anticoagulant)
The dissociation and binding of oxygen by hemoglobin are NOT DIRECTLY PROPORTIONAL to the partial pressure of oxygen (pO2) in its environment but instead exhibit a ______.
Sigmoid Curve Relationship a.k.a hemoglobin-oxygen dissociation curve
What happens to 2,3-DPG if there is a shift to the left result in hemoglobin-oxygen dissociation curve?
Decrease
REMEMBER! (pacheck kay ma’am may problem sa book)
– Pag shift to the left, lahat decrease maliban sa pH and Abn Hb
– Pag shift to the right, pH lang ang decrease
RBC viability is a measure of ____ RBC survival following transfusion.
a. In vitro (Outside or Inside?)
b. In vivo (Outside or Inside?)
b. In vivo (Inside)
The U.S. Food and Drug Administration (FDA) requires an average 24-hour post-transfusion RBC survival of more than ___.
75%
To maintain optimum viability, blood is stored in the liquid state between ______ for a specific number of days
1°C and 6°C
The loss of RBC viability has been correlated with the _____, which is associated with various biochemical changes
Storage lesion
In RBC Storage Lesions state if these characteristics are increased or decreased (Except O2 Dissocation form: Left or Right?).
(a) Viable cells (%)
(b) Glucose
(c) ATP
(d) Lactic acid
(e) pH
(f) 2,3-DPG
(g) Oxygen dissociation curve
(h) Plasma K+
(i) Plasma hemoglobin
(a) Viable cells (%) - Decrease
(b) Glucose - Decrease
(c) ATP - Decrease
(d) Lactic acid - Increase
(e) pH - Decrease
(f) 2,3-DPG - Decrease
(g) Oxygen dissociation curve - Shift to the Left
(h) Plasma K+ - Increase
(i) Plasma hemoglobin - Increase
It has been reported that within the ___ hour after transfusion, most RBC clearance occurs.
First hour
Approximately ______ mg of iron are contained in one RBC unit.
220 to 250
What is the Storage Time if Acid citrate-dextrose (ACD-A) is added? Is it an anticoagulant or additive?
21 Days (Anticoagulant)
What is the Storage Time if Citrate-phosphate-double-dextrose (CP2D) is added? Is it an anticoagulant or additive?
21 Days (Anticoagulant)
What is the Storage Time if Citrate-phosphate-dextrose-adenine (CPD-A) is added? Is it an anticoagulant or additive?
35 Days (Anticoagulant)
All blood stored in all (1) ___ preservatives becomes depleted of 2,3-DPG by the (2) ___ week of storage.
(1) CPD
(2) Second
The 2,3-DPG concentrations after transfusion have been reported to reach normal levels as early as __ hours post-transfusion.
6 hours
Added to RBCs after removal of plasma?
Additive solutions
Storage material where the majority of blood is stored.
Polyvinyl Chloride (PVC) Plastic Bags
Currently approved additive solutions.
AdSol (AS-1) (Baxter Healthcare)
Nutricel (AS-3) (Pall Corporation)
Optisol (AS-5) (Terumo Corporation)
What causes blood units to be more viscous?
High hematocrit
What component of additive solutions protects RBCs against storage related hemolysis?
Mannitol
3 main benefits of AdSols.
- Extends the shelf-life of RBCs to 42 days by adding nutrients
- Allows for the harvesting of more plasma and platelets from the unit
- Produces a packed RBC of lower viscosity that is easier to infuse
What is the advantage of plastic bag containers over glass containers?
It promotes respiration which makes the storage time of RBCs longer.
AdSols reduce hematocrit levels to around __% to __% with a volume of approx. 300-400 mL
55, 65
Additive solutions maintain 2,3-DPG throughout its storage time. In RBCs stored with primary anticoagulant preservatives, 2,3-DPG is not depleted by the second week of storage.
a. Statement 1 is true. Statement 2 is false.
b. Statement 1 is false. Statement 2 is true.
c. Both statements are true.
d. Both statements are false.
D.
None of the AdSols maintain 2,3-DPG throughout its storage time.
In RBCs stored only with primary anticoagulant preservatives, 2,3-DPG is depleted by the second week of storage.
Shelf life of plasma if frozen at temperature <-25 deg. C
3 years
What is the maximum shelf life of autologous units and rare blood types once RBCs are frozen?
10 years
What cryoprotectant is used for RBCs that are less than 6 days old?
20% or 40% glycerol protectant / Glycerol
What is the normal freezing temperature?
-65 deg. C
What are the two concentrations of glycerol that are used to freeze RBCs?
- High-concentration glycerol (40% weight in volume [wt/vol])
- Low-concentration glycerol (20% wt/vol)
Most blood banks that freeze RBCs use the ___
high-concentration glycerol technique
Each unit of whole blood collected contains 450 mL of blood and ___ of anticoagulant or 500mL of blood and ___ anticoagulant.
63mL, 70mL
During deglycrolization , the cryoprotectant is systematically replaced with decreasing concentrations of saline. What are the concentrations?
12% saline followed by 1.6% saline and finally washing with 0.2% dextrose normal saline.
What is the purpose of the deglycrolization process before transfusing frozen cells?
To prevent cells accompanied by hypertonic glycerol and RBC lysis.
What should be monitored to ensure adequate deglycerolization?
Osmolality
Upon the addition of glycerol or saline solutions, the outdating period of thawed RBCs has been ___
24 hours
RBCs in CPD or CPDA-1 are glycerolized and frozen within _____ of whole blood collection
6 days
This is the process of enhancing and restoring ATP and 2, 3- DPG levels by metabolic alterations.
RBC Rejuvenation
RBCs (liquid state) when stored in CPD, CPDA-1, and AS-1 storage solutions can be rejuvenated at outdated or up to _____ after outdated.
3 days
What is the rejuvenating agent used for RBC rejuvenation?
Rejuvesol
What are the contents of Rejuvesol?
phosphate, inosine, and adenine
Rejuvenated RBCs must be washed before infusion to remove the ____ (which is toxic) and transfused within _____.
inosine, 24 hours
Shelf life of platelet.
5 DAYS
State the two main reasons for the 5-day shelf life.
- Bacterial contamination at incubation of 22 degree celsius
- Loss of platelet quality
Main functions of platelet.
Blood coagulation
Treat or prevent bleeding
Approximately ___ to ___ of the platelet inventory is discarded either by the blood supplier or the hospital blood bank.
20%, 30%
Platelets are stored at __ to ___
20°C, 24°C
What is the purpose of continuous agitation of the platelets?
To facilitate oxygen transfer into the platelet bag and oxygen consumption by the platelets.
The loss of platelet quality during storage is known as the _____
platelet storage lesion
What is the the principal buffer during the storage of platelet concentrates (PCs) in plasma?
bicarbonate
Rejuvenated RBCs may be prepared up to __ days after expiration when stored in CPD, CPDA-1, and AS-1 storage solutions.
3 Days
When the bicarbonate buffers are depleted during platelet concentrate storage, the pH rapidly falls to <6.2, what does it mean?
Loss of platelet viability
Membrane integrity
True or False. The pH change to less than 6.2 is irreversible.
True
What is the key parameter for retaining platelet viability in vivo when platelets were stored at 20 degC to 24 degC?
Maintaining pH
Quality-control measurements for platelet concentrates.
Platelet concentrate volume
Platelet count
pH of the unit
Residual leukocyte count
How is visual inspection done for platelets? What is the expected result?
platelet swirl (no visible aggregation)
TRUE OR FALSE
Immediately before distribution to hospitals, a visual inspection is made that often includes an assessment of platelet swirl (no visible aggregation). The presence of platelet swirling is associated with the loss of membrane integrity during storage, resulting in the loss of discoid shape with irreversible sphering.
FALSE
No platelet swirling, meaning there is an aggregation, meaning there is a loss of membrane integrity during storage.
In Vitro platelet assays in relation with in vivo survival
pH
Shape change
Hypotonic shock response
Lactate production
Partial pressure of oxygen
What is the current trend in preparing platelet concentrates from whole blood?
platelet apheresis
Used to measure platelets after transfusion and serves as an assessment for the effectiveness of the transfusion. Measure of the expected increase in platelets following a platelet transfusion
CCI or corrected count increment
Failure to achieve acceptable increase in platelet count following platelet transfusion.
Refractory
Platelet Storage Lesion Characteristics (Increase or Decrease)
(a) Lactate
(b) pH
(c) ATP
(d) Loss of Swirling Effect (Discoid to Spherical)
(e) Degranulation
(f) Platelet Activation Markers
(g) Platelet Aggregation
(a) Lactate - Increase
(b) pH - Decrease
(c) ATP - Decrease
(d) Loss of Swirling Effect (Discoid to Spherical) - Decrease
(e) Degranulation - Increase
(f) Platelet Activation Markers - Increase
(g) Platelet Aggregation - Drop in response to some agonists
A pool of 6 platelet concentrates should achieve an increment of _____ to _____/μL in an average adult.
30,000, 50,000
Platelet count must be measured within ___ hour after transfusion.
1
______ refers to the increase in platelets following a transfusion. ______ is based on the patient’s size and the number of platelets transfused.
Count increment, Correction
CCI is usually determined __ to __ minutes after transfusion
10 to 60
Currently, greater than ___ of platelet transfusions are from apheresed platelets and about ___ are pools of whole blood-derived platelets (WBD)
92%
8%
Formula for CCI
CCI = (postcount/uL – precount/uL) × body surface area (m2) /platelets transfused x 10^11
Factors to Be Considered When Using 5-Day Plastic Storage Bags
- Temperature control of 20°C to 24°C
- Careful handling of plastic bags
- Residual plasma volumes recommended for the storage of platelet concentrates from whole blood (45 to 65 mL)
- For apheresis platelets, the surface area of the storage bags needs to allow for the number of platelets that will be stored.
If the CCI is >____ /uLit is a good increment and if it is <____/uL it indicates that the patient has platelet refractories.
10,000 ; 5,000
Platelet concentrates should contain a minimum of ____ platelets in a volume of between 45mL and 65mL
5.5 x 10^10
Platelet expiration time (FDA)?
midnight of day 5
Purpose of glycerol in RBC Freezing
Acts as a cryoprotectant that preserves RBC membrane viability in freezing
Most common infectious complication of transfusion?
Sepsis due to contaminated platelets
What is the importance of glucose-6-phosphate dehydrogenase?
Pentose Phosphate Pathway (PPP) is used to produce NADPH.
Glutathione is responsible for detoxifying ___? What generates glutathione?
hydrogen peroxide (H2O2), NADPH
True or False. In the ferric state of iron, iron cannot bind to oxygen, which renders hemoglobin useless.
True
