BB Lec - RBC Biology and Preservation Flashcards
two important RBC characteristics:
deformability and permeability
is the network of proteins that contributes shape, strength, and function to a cell membrane.
cytoskeleton
gives RBC their characteristic biconcave shape
cytoskeleton
purpose of biconcave shape of RBCs
to allow gas exchange while carrying great quantities of oxygen
gives a red cell flexibility
strengthens the cell membrane,
facilitates its efficient travel through capillaries
Cytoskeleton
CAUSES OF SPHEROCYTOSIS (4)
defects in: spectrin spectrin and ankyrin anion exchanger palidin
defect in proteins that provides vertical support
HEREDITARY SPHEROCYTOSIS
defect in proteins that provide horizontal support
HEREDITARY ELLIPTOCYTOSIS:
causes of loss of deformability (2)
The loss of adenosine triphosphate (ATP) (energy) levels [leads to a decrease in the phosphorylation of spectrin and, in turn, a loss of membrane deformability]
An accumulation or increase in deposition of membrane calcium also results, [causing an increase in membrane rigidity and loss of pliability ]
loss of ATP leads to ___
decrease in the phosphorylation of spectrin
decrease in the phosphorylation of spectrin leads to
loss of membrane deformability
manifestations of loss of membrane deformability [3]
spherocytes
bite cells
shortened lifespan
cells with a reduced surface-to-volume ratio and in which the
“spherocytes”
what cells
removal of a portion of membrane has left a permanent indentation in the remaining cell membrane
“bite cells”
The RBC membrane is freely permeable to
water and anions
importance of permeability of rbc membrane (2)
prevent colloid hemolysis
control the volume of the RBC
responsible for 90% of ATP generation
EMP
processes/reactions in stage 1 emp
phosphorylation, isomerization, diphosphorylation
end product of emp
end product: 3GP
3rd stage of emp, product:
pyruvate
Produces (reduced) NADPH and reduced glutathione
HMP
prevents iron of Hgb from being oxidized (maintains ferrous state)
Methemoglobin reductase pathway
2,3 DPG generation
RLP
What form
B chains are closer together
Relaxed form
What form
B chains are farther
Tensed form
Is the effect pH has on HGB-oxygen affinity
HGB-DISSOCIATION CURVE
Increase pH is a shift to ?? (inc or dec HGB affinity for O2)
left
increased HGB affinity for O2
example of shift to left
hyperventilation
Decrease pH –> shift to ??( increased or decreased HGB affinity for O2)
right
decreased HGB affinity for O2
example of shift to right
EXERCISE
RENAL FAILURE
is a measure of in vivo RBC survival following transfusion
RBC viability
The FDA requires an average 24-hour post transfusion RBC survival of
more than 75%
biochemical changes due to loss of RBC viability
Storage lesion:
increases ADP levels, thereby driving glycolysis toward the synthesis of ATP
adenine
chelates Ca, prevents clotting
Citrate (sodium citratre/citric acid):
maintains pH during storage; necessary for maintenance of 2,3 DPG
Monobasic sodium phosphate
substrate for ATP production( cellular energy)
Dextrose
prod’n of ATP, extends shelf life from 21 days to 35 days
Adenine
These are preserving solutions that are added to the RBCs after removal of plasma with or without platelets
additive solutions
The additive solution is contained in a ___ and is added to the RBCs after most of the plasma has been expressed
satellite bag
The additive solution is contained in a satellite bag and is added to the RBCs after ___
most of the plasma has been expressed
Benefits of additives (3)
Extends the shelf life of RBCs (42 days)
Allows for the harvesting of more plasma and platelets from the unit
Produces an RBC concentrate of lower viscosity that is easier to infuse
(AS-1; Baxter Healthcare)
Adsol
(AS-3, Pall Corporation)
Nutricel
(AS-5, Terumo Corporation)
Optisol
ALL three additives have (3)
saline, adenine, and glucose.
AS-1 and AS-5 also contains ___ (protects against storage-related hemolysis)
mannitol
AS-3 contains __ and ___ (for the same purpose)
citrate and phosphates
purpose of mannitol, citrate and phosphates
protect against storage-related hemolysis
None of the additives solutions maintain ___ throughout the storage time
2.3 DPG
ALL (AS-1 to AS-5) of the additive solutions are approved for HOW MANY days of storage for packed RBCs
42
Used for autologous units & storage of rare blood types
RBC Freezing
RBC Freezing involves the addition of cryoprotective agent to RBCs that are how many days old
less than 6 days old
2 concentrations of glycerol
high conc-glycerol (40% w/v)
Most BB used high-conc. Glycerol
low conc. Glycerol (20% w/v)
commonly used as cryoprotective agent and is added to RBCs slowly with vigorous shaking to permeate the RBCs
glycerol
FDA licenses frozen RBCs to be stored up ?? years
10
Transfusion of frozen cells must be preceded by a ____ process
deglycerolization
what are the saline conc. in deglycerolization
12% saline, 1.6% saline, 0.2% dextrose in saline
has traditionally been used in the deglycerolizing process.
A commercially available cell-washing system
what must be monitored during deglycerolization
excessive hemolysis
osmolality
has been developed that allows the glycerolization and deglycerolization to be performed under closed system.
ACP 215 (Haemonetics)
Process by which ATP and 2,3 DPG levels are restored or enhanced by metabolic alterations
rbc rejuvenation
only FDA approved rejuvenation solution sold in the US
Rejuvesol:
rejuvenation solution currently approved for use with CPD, CPDA-1 and CPD/AS-1 RBCs
Rejuvesol:
composition of rejuvesol
Contains phosphate, inosine, pyruvate and adenine
temp and time for rejuvenation incubation
1 hr 37C
volume of rejuvenation solution
50 ml
Following rejuvenation, the RBCs can be washed to remove the rejuvenation solution and transfused within how many hours.
24
