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The process Assessment IVF ICSI
Fertilization The process Assessment IVF ICSI
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The Process - sperm capacitation hyperactivation zona binding
acrosome reaction zona penetration sperm-oocyte membrane fusion sperm engulfed decondensation of sperm nucleus formation of male pronucleus
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The Process - Egg Ovulation Sperm-egg membrane fusion Egg activation
increase in Ca++ cortical reaction - zona block completion of meiosis (2nd PB) formation of female pronucleus Syngamy - fusion of both pronuclei
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Capacitation process of sperm becoming fertile occurs in uterus
must be removed from seminal fluid in vitro, wash sperm capacitated sperm have the ability to fertilize the egg
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Hyperactivation facilitates sperm-oocyte contact occurs in oviduct
motility pattern becomes frenzied linear to non-linear motion
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Zona Binding Zona proteins: ZP1, ZP2, ZP3 Sperm bind ZP3 specifically
Initiates acrosome reaction
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Acrosome Reaction Fusion of two membranes Acrosin released
spermatazoal plasma membrane outer acrosomal membrane Acrosin released allows sperm to penetrate zona Exposes equatorial segment for fusion with egg
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Sperm-Egg Fusion Equatorial segment of sperm Plasma membrane of egg
Initiates egg activation
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Egg Activation Cortical Reaction Zona block
exocytosis of cortical granules Zona block biochemical changes eliminates sperm binding
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Assessment of Fertilization
Check for PN hrs post insemination Normal Fertilization 2 PN in ooplasm 2 PB perivitelline space
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Abnormal Fertilization
> 2 PN in ooplasm polyspermic: >1 male PN, 1 female PN, 2PB polygynic: >1 female PN, 1 male PN, 1PB failure to extrude second PB Spontaneous oocyte activation 1 female PN, 2 PB Condensed sperm: 1 female PN, 2 PB Oocyte activation (digynic) >1female PN, 1 PB
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IVF: Why? Humans: overcome infertility Animals: end of reproductivity
male factor: low motility, low count female factor: tubal, ovulatory Animals: end of reproductivity more superior animals Research: IVM with IVF many embryos to study techniques: transgenics, es cells, cloning
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Intracytoplasmic Sperm Injection
Overcome fertilization problems: no penetration ASAB, anti-sperm antibodies very low count (<500,000/sample) very low motility (<20% motile)
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ICSI - process Add sperm to PVP Mature egg w/holding pipet
inert, slows sperm to catch Mature egg w/holding pipet PB at 12:00 or 6:00 Catch sperm and kink tail Load sperm in ICSI pipet Break plasma membrane Deposit sperm
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