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Laboratory Tour
A normal semen sample has a volume of at least 2 ml, and a
concentration of at least 20 million sperm cells per ml, at least 50% of which
show motion. Below are some microscopic video clips of sperm cells in a
semen sample. [When sperm cells are treated with PVP (polyvinylpyrrolidone),
they move slower so that an individual sperm cell can be picked up and injected into an egg using the
ICSI (intra-cytoplasmic sperm injection)
procedure].
Please click on the small pictures
below for a slideshow.
Dr. Yavas preparing media on the day prior to egg retrieval. Dr. Yavas examining eggs upon retrieval. Dr. Yavas checking fertilization in special chamber. Dr. Yavas performing ICSI procedure. Eggs and embryos are cultured in these incubators. Dr. Yavas performing semen analysis in Andrology Laboratory. Sperm and embryos are kept frozen in liquid nitrogen tanks (-196oC/-321oF).
Dr. Yavas preparing media on the day prior to egg retrieval.
The egg (oocyte) is surrounded by cumulus
cells. Hence, it is called "oocyte-cumulus complex."
Please click on the small pictures
below for a slideshow.
An egg stripped off its cumulus cells prior to ICSI. An egg stripped off its cumulus cells prior to ICSI. An egg stripped off its cumulus cells prior to ICSI. An egg stripped off its cumulus cells prior to ICSI.
Please click on the small pictures
below for a slideshow.
The egg is held with a holding pipette. A single sperm cell has been aspirated into the injection pipette and is ready to be injected into the egg. The injection pipette with the sperm cell positioned at the tip is gently pushed against the wall of the egg. The injection pipette is further pushed against the wall of the egg. The injection pipette is further pushed towards the center of the egg. The tip of the injection pipette is in the center of the egg. The injection pipette is further pushed towards the opposite side of the egg. The sperm cell is released into the egg. The injection pipette is withdrawn. The injection pipette is withdrawn.
The egg is held with a holding pipette. A single sperm cell has been aspirated into the injection pipette and is ready to be injected into the egg.
Please click on the small pictures
below for a slideshow.
The spem cell is immobilized with the tip of the injection pipette The sperm cell is aspirated into the injection pipette. The sperm cell is further aspirated into the injection pipette. The sperm cell is further aspirated into the injection pipette. The sperm cell is further aspirated into the injection pipette. The egg is held with a holding pipette. A single sperm cell has been aspirated into the injection pipette and is ready to be injected into the egg. The injection pipette with the sperm cell positioned at the tip is gently pushed against the wall of the egg. The injection pipette is further pushed against the wall of the egg. The injection pipette is further pushed against the wall of the egg. The injection pipette is further pushed towards the center of the egg. The tip of the injection pipette is in the center of the egg. The injection pipette is further pushed towards the opposite side of the egg, and the sperm cell is released into the egg. The injection pipette is withdrawn.
The spem cell is immobilized with the tip of the injection pipette
Please click on the small pictures
below for a slideshow.
With the use of
sophisticated micromanipulation techniques in ICSI, a single sperm cell is
isolated and injected into each mature egg. The egg has a diameter of 110
micrometers, whereas the head of a sperm cell has a length of 4-5 micrometers,
and a width of 2.5-3.5 micrometers (1 micrometer is one-thousandth of a
millimeter). The egg is held with a holding pipette. A single sperm cell is
aspirated into the injection pipette that has an inner diameter of 5-7
micrometers, and then is injected into the egg.
You can enlarge the following images by clicking on
them.
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JUST BEFORE ICSI:
A mature egg just before the ICSI procedure. On the left side, the egg is held with a holding pipette. On
the right side, a single sperm cell has already been aspirated into the
injection pipette. The sperm
cell is positioned as close to the tip of the injection pipette as
possible, and is ready
to be injected into the egg.
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DURING ICSI: The injection pipette has been inserted
into the egg; the sperm cell positioned at the tip of the injection pipette
is soon to be released into the egg.
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FERTILIZATION:
A fertilized egg after ICSI or conventional in vitro
insemination. At as early as 12 hours after ICSI or in vitro insemination, the fertilized
egg begins to display two pronuclei in the center; one pronucleus from the male, and the
other one from the female. The genetic material is also visible in both
pronuclei.
The pronuclei begin to disappear around 18-20 hours after ICSI or
in vitro insemination.
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2-CELL
EMBRYO ON DAY 2 (DAY 0 = EGG RETRIEVAL): The fertilized egg has
undergone cleavage, resulting in two blastomeres.
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4-CELL
EMBRYO ON DAY 2: The 2-cell embryo has
undergone further cleavage, resulting in four blastomeres.
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8-CELL
EMBRYO ON DAY 3: The 4-cell embryo has
undergone further cleavage, resulting in eight blastomeres.
This embryo is now ready to be replaced in the uterus. Alternatively, it can
also be cultured further for blastocyst development.
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MORULA
ON DAY 4: The 8-cell embryo has undergone further cleavage. The
multiplying blastomeres are no longer distinct, forming a "morula".
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BLASTOCYST
ON DAY 5: The size of the embryo has increased, and the
zona pellucida (the layer surrounding the egg) has become thinner. A
cavity has formed inside the morula, filled with fluid. The inner cell
mass (ICM; at 5 o'clock position) will eventually form the fetus
after implantation in the uterus. This blastocyst is now ready to be
replaced in the uterus.
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HATCHING BLASTOCYST ON DAY 5 OR 6:
Occasionally, the blastocyst may begin to hatch (get out of its surrounding zona
pellucida) even before it is replaced in the uterus. This
blastocyst is now ready to implant in the uterus upon embryo transfer.
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