February 09, 2019 Saturday
Bedtime Story
Understanding Erythrocyte Sedimentation
Sedimentation rate is simply a measure of
the rate at which the erythrocytes or the red blood cells or the RBCs stack up
when coagulation factors are taken care of.
This means this test is carried out in
conditions when the RBCs are not allowed to take part in the coagulation
process or let the process of the formation of the clot interfere with its
settling down due to gravity.
Although clotting does not directly
involves the RBCs – the prime mediator of clotting being platelets – but you
can very well imagine that carrying out sedimentation test or the Biernacki
Reaction (as a Pole would like it to be called) would be virtually impossible
in a tube that is laden with clots all around.
Just as another aside, clotting is one of
those biological processes that is highly conserved throughout biology.
What this means is this; one a life form of
mammal say our rodent ancestor by series of chance events found a way to
“figure out” that leaking capillaries in a site of tissue injury could be
plugged through a mixture of cells and proteinaceous glue (fibrin) via a
cascade of simple reactions, the other life forms said “thank you”.
The other life forms that evolved later “grasped”
upon this chance event that might have come up just once in our evolutionary timeline
and held on to it tenaciously as a highly prized asset of survival.
Of course later the arms race between
predators and the prey would have only perfected the system over generations
simply by the fact that the individuals with imperfect coagulation system would
have mercilessly bled to death.
Yes, this is how we have come to be – on
the sufferings and death of countless mammalian and non-mammalian ancestors who
are not only unrecognized but are largely unknown even to learned evolutionary
biologists.
So once clotting as an extraneous factor is
taken care of with the help of certain chemicals (such as
ethylenediaminetetraacetic acid or more commonly known as EDTA) ESR can then be
performed.
EDTA is a synthetic chemical that has this
unique ability to sequester metal ions such as Ca2+ and Fe3+.
Since the calcium ions is a necessary
element in the clotting process its capture by EDTA prevents blood from
clotting.
This helps in preserving the blood cell
morphology making it a valuable medical tool as most medical interns would know.
Now when the RBCs are left in the
Westergren tubes to settle down two or three factors decide how the cells will
sediment.
First is of course gravity which is assumed
to be uniform all over the planet earth at least for our medical diagnostic
purposes.
But the other pro-sedimentation factor that
concerns the physicians (and thereby the patients) most is the fibrinogen which
is a glycoprotein manufactured by the hepatocytes.
Fibrinogen is an important component of the
clotting process.
Besides this Fibrinogen is a positive
active-phase protein.
Stay tuned to the voice of an
average story storytelling chimpanzee or login at http://panarrans.blogspot.com
Good night Mon Ami and my fellow cousin ape.
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Another great educator and a teacher that I am aware of is
Professor Subhashish Chattopadhyay in Bangalore, India.
While I narrate stories, Professor Subhashish an electronic
engineer and a former professor at BARC, does and teaches real mathematics and
physics.
He started the participation of Indian students at the
International Physics Olympiad.
Do visit him here:
All his books can be downloaded for free through this link:
For edutainment and English education of your children, I
recommend this large collection of Halloween Songs for Kids:
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