PSIO 469 Exam 3 Flashcards
1
Q
In what situations is sperm banking used in?
A
Vasectomy, Cancer, IUI/ART, High risk occupational exposure.
2
Q
In what situations is egg banking used in?
A
Cancer, Delaying reproduction, failure to obtain sperm on retrieval day
3
Q
How old do sperm and egg donors need to be?
A
Egg 19-30 Sperm 20-39
4
Q
why is sperm quarantined for 6 months?
A
After an initial testing, there may be no detection. Waiting 6 months and repeating testing may increase the likelihood of identifying any infections that were initially undetectable.
5
Q
What is cryopreservation?
A
Cooling cells or tissues by preserving them outside the body. Temp should be about -196 C or 321 F.
6
Q
How are cells protected from freezing injury?
A
- Controlled cooling and thawing rate
- Addition of cryoprotectants- reduce the formation of ice crystals within the cells- this minimizes cell damage.
7
Q
What causes extracellular crystal formation?
A
As the temp. decreases during cooling, water molecules in the extracellular space begin to form ice crystals.
8
Q
Decrease in water content causes the concentration of solutes to ___?
A
Increase
9
Q
what is a hypertonic solution?
A
Hypertonic solution has a higher concentration of solutes compared to another solution.
10
Q
What causes cells to become dehydrated?
A
Hypertonicity
11
Q
what do cryoprotectants do?
A
Increase the osmolarity of the extracellular fluid effectively lowering its freezing point and preventing intracellular ice formation.
12
Q
why is dehydration beneficial?
A
It helps minimize intracellular ice formation by reducing the amount of water available within the cell.
13
Q
define solute effect and intracellular ice formation:
A
Solute Effect: Freezing too slowly allows too much dehydration.
Intracellular ice formation: Freezing too rapidly allows too much intracellular ice formation.
14
Q
what are optimal sizes of sperm, embryo and oocyte?
A
sperm is about 5-60 micrometers. Embryo is 40 micrometers. Egg is 130 micrometers.
15
Q
permeating vs non-permeating?
A
Permeating: Small molecules are able to cross membrane and enter the cell. Able to form hydrogen bonds with water ( this may prevent or slow ice crystal formation) ex: glycerol
Non-permeating: Larger molecules that do not cross cell membrane and remain extracellular. Slow or prevent extracellular ice formation. Often used in combination with permeating. Ex: Sucrose
16
Q
what is the post-thaw motility rate for sperm?
A
20-65%
17
Q
what causes lowered sperm motility post-thaw?
A
Decreased integrity of membrane, altered energy metabolism and synthesis.
18
Q
why is oocyte freezing not the best?
A
meiotic spindle is highly sensitive to temp. Microtubule and microfilament damage may lead to abnormal division of chromosome. Freezing oocyte may damage cortical reaction and an impaired corticol reaction may increase the risk of polyspermy. Ice crystal formation may also cause mechanical stress on zona pellucida.
19
Q
why should ICSI be used in frozen oocyte?
A
Direct injection allows bypassing the need for sperm to pass through the zona pellucida which may be challenging.
20
Q
what are stem cell characteristics?
A
- self-renewing
- unspecialized
- can give rise to specialized cells
21
Q
what is a totipotent stem cell?
A
A cell that can develop into any cell in the body, including extra-embryonic membranes (trophectoderm and chorion)
22
Q
what is a blastomere?
A
A single cell from a 2-8 cell ( day 1-3) embryo.
23
Q
Chimeric organism:
A
A single organism that is composed of two or more genetically distinct cell lines that originated from different zygotes.
24
Q
Inner cell mass of day 5 can give rise to all… except ____
A
chorion
25
What is multipotent?
can become specialized cell or organ in which it resides.
26
what are the steps involved in making embryonic (pluripotent) stem cell?
1. Create embryo 2. Remove inner cell mass from blastocyst (day 5) 3. Culture cells
27
what type of cells are embryonic stem cells?
Totipotent or pluripotent
28
What type of cells are adult stem cells?
multipotent
29
embryonic stem cells are derived from ____
inner cell mass of developing blastocyst.
30
What are tests to identify embryonic stem cells?
1. grow and sub culture cells for months. 2. Look for surface proteins that are found in undifferentiated cells (OCt4) 3. examine chromosome under microscope (karyotypes) 4. determine if cells can be grown and subcultured after freezing, thawing 5. demonstrate differentiation potential.
31
what is spontaneous differentiation?
Stem cells are allowed to differentiate in a culture without the addition of signaling molecules or external cues. Cells usually clump and form 3-dimensional aggregates.
32
what is directed differentiation?
Manipulate the stem cells using growth factors.
33
what does the presence of oct-4 indicate?
That a stem cell is in an undifferentiated state
34
what does the presence of PAX6 indicate?
gives insight into developmental lineage or differentiation status of cell population.
35
what is a teratoma?
It is a tumor that contains a mixture of tissues derived from all three germ layers.
36
How can teratoma be formed?
By injecting pluripotent stem cells into immunocompromised mice.
37
what does the presence of teratoma tell us?
That the pluripotent stem cells are capable of differentiating into a wide range of cell types.
38
what technique is used to assess the pluripotency and developmental potential of pluripotent stem cells?
tetraploid complementation
39
what is regenerative medicine?
branch of medicine that develops to regrow, repair or replace damaged or diseased cells, organs, tissues.
40
what does regenerative medicine include?
Artificial organs, therapeutic stem cells
41
what are some challenges with stem cells and regenerative medicine?
Has to be free of animal products, avoid harming recipient in any way, be able to differentiate into desired cell type
42
Explain the process of SCNT:
In somatic cell nuclear transfer, somatic cell is collected from an organism to be cloned. The Nucleus of the somatic cell is transferred to an enucleated oocyte from a female egg donor. After nuclear transfer, the reconstructed egg cell is stimulated for cell division by electric fusion. Egg cell undergoes division and forms a blastocyst.
43
Explain why SCNT does not result in true clones?
Because the somatic cell and the egg come from different and unrelated individuals. Cloned embryo produced will inherit its mitochondrial DNA soley from the egg cell, and not the somatic cell donor.
43
mutations in mitochondrial dna are linked to?
deafness, neurological and muscle/heart problems, type II DM
43
What is mitochondrial DNA transfer?
Aims to transfer nuclear DNA from the intended parents embryo to a donor embryo with healthy mitochondria.
44
describe the role of mifepristone and misoprostol:
Mifepristone is an anti-progesterone drug, it prevents progesterone from keeping the myometrium quite. Misoprostol is a prostoglandin E1 derivative, it causes cervical dilation and fetal expulsion.
45
define infertility:
Inability to achieve a pregnancy after 12 months of unprotected intercourse
46
list some potential causes of infertility in females:
endometriosis, pcos, chemotherapy, ovulatory dysfunction
47
list some potential causes of infertility in males:
spinal cord injury, testicular injury, infection
48
What does FSH levels on day 3 indicate?
increase in FSH levels on day 3 indicate there are fewer eggs remaining or that the remaining eggs are of low quality
49
what parameters are measured in sperm analysis?
-volume
-liquifaction
-viscosity
-concentration
-motility
-WHO morphology
50
what are the normal range values for sperm volume and liquefaction time?
volume greater than 2.0 mL, liquefaction less than 60 minutes
51
what are the normal range values for sperm viscosity and concentration?
viscosity should be moderate to low, concentration should be greater than 20 x 10^6 mL
52
what are the normal range values for sperm motility and WHO morphology?
motility greater than 50%, WHO morphology greater than 15%
53
in what ways are most infertility cases treated?
progesterone to treat luteal phase defect, metformin and exercise for pcos, fertility drugs with IUI, surgical removal of uterine polyp or septum
54
what is the difference between polyp and septum?
polyp is non-cancerous growth attached to endometrium extending into uterine cavity. Septum is a wedge like partition within uterine cavity
55
how does a polyp cause infertility?
may interfere with fertility by affecting the implantation of a fertilized egg in the uterus. Can disrupt the normal structure of uterine lining.
56
how does a septa cause infertility?
create an abnormal uterine cavity, may increase risk of miscarriage, cause problems with proper development of the embryo.
57
why does IVF account for 3% of infertility treatment?
due to cost, emotional stress, complexity, success rate
58
what does intrauterine insemination (IUI) include?
1.may involve controlled ovarian stimulation
2.Transvaginal ultrasound
3.trigger ovulation at appropriate time
4.Intrauterine insemination
59
at what point is ovulation triggering using hCG injection or medications?
when one or more mature follicles are identified
60
why does ovarian stimulation not deplete future follicle reserve?
Because ovarian stimulation does not induce the recruitment of new follicles, rather it promotes growth and maturation of the existing pool of follicles that would have otherwise been destined for atresia.
61
what male and female characteristics are required for IUI?
female has to be less than 45 yr and have open tubes. Male needs to have greater than 10 million sperm/ml, with greater than 35% motility
62
what does ART stand for and what does it mean:
Assisted Reproductive Technology- any procedure where sperm and oocytes are handled outside body.
63
who was the first patient to have a successful IVF trial?
Louise Brown
64
who won the fist Nobel prize for IVF and in what year?
Robert Edwards in 2010
65
In what year was the first IVF baby born?
1978 in Britain
66
In what year was the first IVF baby born in the united states?
1981
67
what are the steps involved in IVF?
1.Controlled ovarian stimulation
2.Prevention of premature ovulation
3.Trigger LH surge when appropriate
4.Egg retrieval
5.Fertilization (possible ICSI)
6.Embryo culture
7.Fresh embryo transfer
68
in IVF what is the goal number of follicles?
8-15 good follicles
69
what could you give a patient to prevent premature ovulation?
GnRH antagonist, and GnRH agonist (repeated daily doses)
70
define agonist and antagonist?
Agonist:stimulates action Antagonist: Inhibits action
71
what medication can be given to patient to cause or mimic LH surge?
hCG injection or GnRH agonist (single dose)
72
What is responsible for producing progesterone during the early stages of pregnancy?
corpus luteum until placenta takes over
73
egg retrieval destroys the follicle and prevents formation of a normal corpus luteum. if an IVF patient becomes pregnant, how long should she continue taking supplemental progesterone?
10 weeks
74
what happens during sperm capacitation?
sperm becomes hyperactivated and gains the ability to penetrate the eggs protective layer.
75
what are some concerns regarding ICSI?
Since a single sperm is injected into oocyte, there is a possibility of damage to the egg during the procedure. Since the process skips sperm capacitation, there are concerns that there may be long-term health issues with offspring conceived.
76
once a patient starts menses, what medication could give her to suppress follicle growth and ovulation, and stimulate endometrial proliferation?
Estradiol because at the start of menses she will be in follicular phase, and high estradiol plays a negative feedback loop on hypothalamus and AP to release less LH.
77
For a patient considering frozen embryo transfer (FET) when should she take progesterone?
Day 14, following ovulation. Progesterone prepares uterine lining for embryo implantation
78
what happens on day 1, 3, and 5 of embryonic development in culture?
Day 1: fertilized oocyte with 2 pro-nuclei (2-4 cell stage)
Day 3:Cleaved embryo (8-cell stage)
Day 5: Blastocyst
79
success rates for IUI are ____ compared to IVF
lower
80
success rates for IUI range from _____ while for IVF range from ____
IUI: 5-15% IVF:10-45%
81
why is frozen embryo transfer better than fresh embryo transfer?
Better endometrial receptivity- Endometrium has a better ability to successfully attach the blastocyst and nourish it and keep it alive.
82
what is a frozen embryo transfer?
when embryos created by IVF are cryopreserved and stored for future use.
83
what is the difference between traditional surrogate and gestational carrier?
In traditional surrogate, the surrogate is inseminated with sperm from male of infertile couple (no IVF is required) and surrogate is genetically related to child. In gestational carrier, they carry embryo created by egg and sperm of two other individuals (requires IVF). Gestational carrier is not genetically related to child.
84
what is included in CDC ART report?
all fertility treatments in which BOTH the eggs and sperm are handled outside the body.
85
why is 2021 ART data published in late 2023?
ART success rates are based on live births. Every ART pregnancy has to be followed up to determine whether brith occured. Earliest clinics can report complete annual data is late in year after ART treatment was initiated.
86
Explain why not all patients who start an IVF cycle have an embryo transfer?
Cycles may be cancelled for poor ovarian response, illness, other medical or personal reasons. Transfer may be cancelled due to poor uterine lining development, poor or no embryo development, medical or personal reasons, or desire to bank eggs or embryos.
87
what is a pregnancy?
Positive hCG blood test at 4 weeks gestation, chorionic sac is present at 5-7 weeks gestation (clinical pregnancy) detection of heartbeat at 7 weeks gestation (clinical pregnancy) then live birth
88
Miscarriage rates increase significantly in mid to late ____
30s
89
Most miscarriages occur prior to ___ weeks
14
90
Transferring 2 embryos increases live birth rate by only ___ % but increases chance of twins or more by ___%
6.2% , 39.2%
91
Monozygotic twinning is more common with ___
ART
92
DIzygotic twinning is more common in ___ childbearing.
Delayed ( 35 yr and older)
93
why is the chance of dizygotic twinning higher in older females?
Because as women age, ovarian reserve declines, and they may release higher levels of FSH, which can lead to release of multiple eggs during ovulation.
94
what are some complications of multiple gestation?
-preterm birth
-death within one month of birth (7 times more likely for twin and 20 times more likely for triplet)
-prematurity
-Intrauterine growth restriction
95
what are some maternal complications in multiple gestation?
-Pre-eclampsia (pregnancy induced hypertension)
-placental abnormalities and maternal hemorrhage
-may require c-section
-gestational diabetes, anemia, excess amniotic fluid
96
why did Dr.Kamrava lose his medical license in california?
transferred excess amount of embryos in patients uterus during IVF- resulted in birth of 8 babies.
97
who is baby boy curtis?why is his story remarkable and controversial?
He was born at 21 weeks and 1 day weighing 420 grams. Babies born less than 23 weeks and 400 grams are not viable but he survived.
98
why is eSET preferred for IVF?
to reduce risk of multiple pregnancies.
99
what does eSET stand for?
Elective Single Embryo Transfer
100
What is multifetal pregnancy reduction?
a procedure done to reduce the number of fetuses. Usually done in the first-trimester or early second-trimester.
101
How can multifetal pregnancy reduction be avoided?
-limit the number of embryos transferred
-preimplantation genetic testing (allows for screening of embryos for chromosomal abnormalities or genetic disorders before they are transferred to the uterus)
102
what concern is raised in regards to induced pluripotent stem cells?
iPSC process inactivated tumor-suppressing pathways and activates oncogenic ones (c-Myc is oncogenic)
103
what is a concern with the original yamanaka factors?
the original yamanaka factors were introduced with the infection of retrovirus, so they were permanently integrated into the genome.
104
what is a recent modification to the original recipe (yamanaka factors)
CRISPR/Cas9
105
what evidence did Vierbuchen demonstrate?
That with three genes or transcription factors they were able to convert fibroblasts into functional neurons (iN or induced neuronal cells)
106
why is it too early to abandon SCNT?
not clear if iPSC and other reprogramming is safe for human use. Rate and efficiency of conversion is very low for iPS as of right now. Reprogrammed stem cells appear to carry epigenetic "memory" as evidenced by DNA-methylation patterns.
107
what did the Hu study demonstrate?
hESCs (human embryonic stem cell) are more efficient at cell conversion and differentiation compared to other cell types such as iPSCs, fibroblasts or other somatic cells.
108
why is PAX6 an important transcription factor?
Expression of PAX6 is significant in the process of cell conversion and differentiation, particularly in the generation of neurons (neuroepithelial cells).
109
what does troublesome memories refer to?
some epigenetic marks from the original somatic cell may not be fully erased during the reprogramming process. These epigenetic marks can influence the behavior and differentiation of potential iPS cells, leading to "troublesome memories".
110
what is the main difference between Gene therapy and Cell therapy?
Gene therapy= treat or prevent disease. Cell therapy= transplantation/cellular injection into diseased patient.
111
what are ethical concerns with germ line editing but not somatic cell editing?
Somatic Cell editing targets adult stem cells, and will only treat disease in affected individuals. Germline gene editing will target zygote and gametes, this will modify all cells in organism. the affected person will not be treated but their offspring will be.
112
who was CC2001 and why did he looked different than original cat?
First cloned pet. CC was genetically identical to original donor cat (shared same nuclear dna) however due to epigenetic factors and env influences affected gene expression and phenotype. CC looked diff that somatic cell donor.
113
what does Barry body formation ensure?
It ensures that females do not produce twice the amount of gene products encoded by X-linked genes as males who only have one x-chromosome.
114
define Euploidy
normal compliment of chromosome
115
define Aneuploidy
Abnormal number of chromosome
116
define Trisomy
presence of additional (third) chromosome of one type. 2n+1
117
define Triploidy
3 complete sets of chromosomes. 3n
118
