Class Notes (1,100,000)
CA (620,000)
UTSG (50,000)
CSB (500)
CSB351Y1 (100)

Lecture 23

Cell and Systems Biology
Course Code
Mounir Abou Haidar

This preview shows pages 1-3. to view the full 12 pages of the document.
Lecture 23- November 29th 2007.
Everything will be written VERBATIM
Pages: 139, 140, 145, 146, 147, supl. to 153 16 of 18 and 17 of 18.
page 139 (or 60 of 166 in the pdf file 2)
Let’s continue please guys. Influenza virus. We’re going to finish fast
today. Complication of influenza virus is Reye’s syndrome. Reye’s
syndrome is a rare, but serious disease. Sometimes it appears in
children under the age of 20. When they are either infected by the
chicken pox or the flu and they are associated with having aspirin, they
are going to take aspirin. So it is not a clear-cut connection but it might
be, a coincidence or not, I don’t know, but it has been reported.
So what is Reye Syndrome? It affects the brain and sometimes the liver
and sometimes you have persistent vomiting for at least 12 hours or
longer. Clearly is it not a worldwide virus or whatever, stomach flu is
not the correct terminology anyway. Then they have strange behaviour
and also some aggressive behaviour. The symptoms usually develop
after 3-7 days of the viral illness. In some cases the Reye Syndrome
can lead to seizure, a coma, and possibly death. It is rare, but it is
maybe associated maybe with influenza virus and chicken pox, which
we are going to see a bit later.
These are complications. Anti-viral agent, I went through them a bit
last time. Anti-viral agent like for the Influenza. The most common one
is the neuraminadase inhibitor, which is the name of acyclovir and the
trade name is tamiflu. The TAMIFLU inhibits the neuroamindase,
which means the neuroamindase won’t be able to cut the SIALIC
acid into the release of the virus. Amantadine and Rimantadine
(blocks the M2) was, but is not anymore useful because it mutated and
changes against the M2, the proton pump as you remember.
Page 139
Alright, now just the terminology. You have a table like this, which is
fine. I will never ask you how it is taken, oral or by injection or
whatever. I don’t care, at least you know that it the most common one
is the tamiflu or the most efficient one and soon it will probably not be
Alright, now the Guillain-Barre Syndrome, which could be associated
with the influenza virus, but usually it is associated with a Duvenhage
virus. The Guillain-Barre syndrome is a demyelination of the schwann
cells. Schwann cells are the cells that have myelin (the fatty stuff in

Only pages 1-3 are available for preview. Some parts have been intentionally blurred.

the brain), which line the neurons. It is like an electrical wire. The
copper inside the wire is the neurons, the copper wire, then the plastic
around it, is the schwann cells. Those schwann cells, which are
myelinated cells. Some virus such as the Duvenhage virus and maybe
the influenza virus can reach the brain and can kill some of those cells.
So you get some short circuiting of the neuron and you get all kinds of
symptoms, but these are reversible because the neurons themselves
are not destroyed, only the schwann cell. So those symptoms like for
example paralysis, descending paralysis. There is ascending paralysis
radiating pain in the arm and in the neck. Then followed by agitation
and increased respiration rate the muscle stops and in some extreme
cases you have coma and death. But, those are usually quite reversible
which means once the virus is gone the syndrome is generally
reversed back, because as I said there is no damage to the neuron. So
that is what it ends up with. This is called a Guillain-Barre Syndrome.
The Duvenhage virus is similar to the rabies virus which we are going
to see today. Now the last thing about influenza viruses is how do we
name them.
Chart on page 139 (7:20)
How do you do the classification. This year, the strains you look at
them as you put A. A means influenza type A. That’s the one as you
know. It is the serious one, which can infect humans, birds, and pigs.
That is the one in which you can have antigenic shift, OK, that is
Page 140 (he is referring to the first diagram on the page) 7:35
Usually the first letter tells you that it is type A. In this case the SSR is
the origin of it. There is a graphic distribution. And there is a strain
number because in this business they have the strain, they number
them, you don’t have to worry about the numbers. And the year, the
year of the virus, the isolation of the strain. Then they tell you also that
H1 is the hemoglutinin type 1 and the neuroaminadase N1 or
whatever, N2, N3, etc. This year, you don’t have to memorize it. This
year, influenza or the flu vaccine is the following, you don’t have to
memorize it. This is for the regular influenza which means inactivated
virus, or killed virus, which I am going to explain to you. It is a live
attenuated virus. LAIV is live attenuated virus. This is recent, those are
the last couple of years. They are allowed, which means they do the
mixing. Learn how they do the influenza virus, the vaccine. It is very
simple. They collect the strain from people who have influenza, say
last year in the winter. They collect them from all different parts of the
world. WHO (world health organization), you have labs in Canada, in
hospital, in US, in Norway, in Europe, in India, whatever. They collect
all these strains, which they collect them from patients. Patients who
have the flu. Usually older guys, who they get the influenza. They

Only pages 1-3 are available for preview. Some parts have been intentionally blurred.

collect the strain from them. Since the influenza virus grows in chicken.
That is the best way of growing them in the lab. They collect them
from patients, they number them, they identify them. Because you
have antibodies to them. So those are the circulating strains among
the populations around the world. They collect them all. Then they
decide in the summer, not in the winter, in the summer that we are
going to grow those strains which are circulating among people and
what is going to happen this year among people before we go to the
vaccine, all of these strains which is going into people go into mixed
exchange, because when you sneeze on somebody and they get it
from somebody else and they mix, and you get a new variant,
variation. So they do all this mixing in the lab in the summer. They
collect all the strains, they include them there and they mix them and
they produce tons of them in embryonic chicken eggs. The eggs you
get at home from Loblaws, those are not fertilized eggs. They don’t
have rooster in these parts. Hens lay the eggs and they don’t want
them to be fertilized because once they get fertilized they start having
an embryo, and if you leave the egg for two or three weeks, even at
room temperature, you start having a small embryo. You start seeing
some blood when you open the egg to eat it. You find some blood in it.
So those are not fertilized eggs. But, the natural stuff, the hens have
roosters and the eggs are fertilized and they start developing and how
the chicken eggs grow. The eggs of chicken, the hen sits on them at 42
degrees. At a body temperature of 42 degrees. It sits on the eggs for
21 days, from laying the egg, the fertilized egg, in 21 days you have a
new chick coming out. 21 days. That is how long it takes, very fast.
But, you sit on it, they have to warm it. So in the lab you put them at
42 degrees. You put tons of fertilized eggs in an incubator at 42
degrees. But, you have to turn the eggs even in the lab, you have to
turn them at least once or twice a day. Just turn it upside down,
because in nature when the hens go sit on the egg it sits on it and
moves them a bit to sit on them, so during evolution they have to be
turned. In the lab you have to turn it because there are no hens
around. So in 15 days or so which means the embryo is almost
complete, so they take the influenza virus with the needle through the
egg, which will still have the shell and they inject the virus into
embryonic chicken, which means it is like in the little chicken inside the
egg. And they have millions of those. They mix the strain, they grow
them and they mix them in live embryonic eggs. So these viruses, they
mix, it is like what is going to happen during the winter. Everything
that is coming out of the mixture is collected and they grow tons of
them. Literally tons of the virus, they kill all these embryo and they
sucks the virus out of it and purify the virus, which is a mixture of all
these strains and whatever counts as the reassortment. And they take
that purified virus and add FORMALIN to it. Formayl to kill it, to pickle
it. If I donate my body for medical school they put me in a FORMALIN
You're Reading a Preview

Unlock to view full version