Exam #3
Principle of Beneficence/Non-malfeasance
"first, do no harm", human life in whatever form, should not be damages without reason and good cause, maximize benefits minimize harms, goodness, try not to damage human goodness, harm outweighs the benefits
Enroll 1000's of patients
A Phase 3 clinical trial will typically... Enroll 10's of patients Enroll 100's of patients Enroll 1000's of patients Be conducted following the approval of a drug to determine long-term safe
Teratoma
A bizarre tumor usually found on the gonads containing what appears to be tissue from all 3 germ layers (skin, muscles, bone, hair, teeth), shows that iPSCs are pluripotent because they can form these, formation of tumors is indicative of iPSC's embryonic stem-cell like properties, benign tumors when they do develop (do not metastasize), typically done in immunodeficient mice,
Safety and Utility
A stem cell clinic in Panama markets an expensive autologous mesenchymal spinal cord injury treatment that is not harmful but is completely ineffective. This violates the bioethical principal of __________.
Non-commercialization
A stem cell researcher collects donor stem cells that he claims are for research purposes but later sells them to a physician who runs a stem cell clinic where the cells are marketed as a treatment for back pain without permission. This violates the bioethical principle of __________.
Progenitors ultimately form only one type of differentiated non-dividing cell when they differentiate (more often unipotent)
As defined in lecture, how is a progenitor cell is different from a stem cell? Progenitors can only divide once and they do this asymmetrically Progenitors generate a broader lineage of cells in vivo than do stem cells Progenitors don't divide Progenitors ultimately form only one type of differentiated non-dividing cell when they differentiate (more often unipotent)
after about 8 weeks, because all organs are formed by this point
At what point in life is an embryo considered a fetus, and why?
Unipotent
Cells will divide to ultimately generate ONE other type of cell, if that cell is a differentiated cell then they are called progenitors, all descendants of stem cells, often have the suffix -blast, not usually thought of as stem cells but when they are they are progenitors
potential vs. structure
Discrepancies in public belief around the beginning of life typically center around different values being placed on ________ vs. _________.
In Phase 4 because they cause severe side-effects in subpopulations of patients that were not detected initially
Following FDA approval for a BLA/NDA, most drugs/biologics will fail in what stage and for what reason? In Phase 1 because they are not safe for humans In Phase 2 because they are not effective in humans In Phase 3 because they are not profittable In Phase 4 because they cause severe side-effects in subpopulations of patients that were not detected initially
In Phase 2 because they lack efficacy in humans
Following FDA approval for an IND, most drugs/biologics will fail in what stage and for what reason? In Phase 1 because they are not safe for humans In Phase 1 because they are not effective in humans In Phase 2 because they lack efficacy in humans In Phase 3 because they cause severe side-effects in subpopulations of patients
Blastocyst
Generated by compaction and differentiation about 5 days after conception, Consists of trophoblasts (the cell on the outside, forms the placenta, tissues needed during development) and embryoblasts (ESCs, the inner cell mass (ICM), become so compact as to leave a fluid filled space inside the blastocoel), At 14 days, implants into the wall of the uterus shedding the zona pellucida, 60-300 cells
cells are taken from the inner cell mass of unused embryos following in vitro fertilization
How are human embryonic stem cells lines used for research typically derived? cells are taken from the inner cell mass of unused embryos following in vitro fertilization cells are taken from fetal tissue following abortions cells from the skin are induced to express 4 genes cells are taken from parts of organs in adults that contain cells used to maintain growth in that organ
They are pluripotent, generating all the body's cell types They can form adult chimeras when put back into embryos that are then allowed to grow up into mice They can form teratomas when injected into the gonads of an adult, immune compromised mouse
How are iPSC similar to ESC? Choose all that apply. They are pluripotent, generating all the body's cell types They present ethical dilemmas associated with the destruction of a fertilized egg they are both obtained by using a virus to reprogram cells They can form adult chimeras when put back into embryos that are then allowed to grow up into mice They can form teratomas when injected into the gonads of an adult, immune compromised mouse ESC and iPSC genomes contain exactly the same epigenetic markings
The clinics claim they perform surgery, because the patients own cells are moved to another location in their body after minimal manipulation
How do stem cell clinics that perform non-F.D.A. approved procedures operate in the United States? The F.D.A. governs drugs, but not stem cell treatments The F.D.A. allows these clinics to operate in cases where there is no other therapy for the intended use on the market currently The clinics claim they perform surgery, because the patients own cells are moved to another location in their body after minimal manipulation The clinics are allowed to perform stem cell transplants that have undergone clinical trials successfully in other countries as an exception
Totipotent -Can generate all cell types, even extra-embryonic membranes. EXAMPLE: the zygote Pluripotent -Can generate all cell types within the body (typically), but cannot generate extra-embryonic membranes. EXAMPLE: embryonic stem cells Multipotent-Can generate all of the different cell types from a single organ or for a single germ-layer. EXAMPLE: neural stem cells Oligopotent -Can generate two or three types. EXAMPLE: NG2 cells
Match the degree of potency to the stem cell that fits the description Potency: -Totipotent -Pluripotent -Multipotent -Oligopotent Stem Cell: -Can generate all cell types within the body (typically), but cannot generate extra-embryonic membranes. EXAMPLE: embryonic stem cells -Can generate all cell types, even extra-embryonic membranes. EXAMPLE: the zygote -Can generate two or three types. EXAMPLE: NG2 cells -Can generate all of the different cell types from a single organ or for a single germ-layer. EXAMPLE: neural stem cells
cleavage - morula fertilization - zygote blastulation - trophoblasts and embryoblasts neurulation - the neural tube and neural crest gastrulation - ectoderm, mesoderm, and endoderm
Match the stage of embryogenesis to the name of the structures formed during that stage Stages: Cleavage Fertilization Blastulation Neurulation Gastrulation Structures formed: zygote the neural tube and neural crest trophoblasts and embryoblasts ectoderm, mesoderm, and endoderm morula
1952- SCNT first performed 1981- mouse embryonic stem cells isolated 1998- human embryonic stem cells isolated 2007- human iPSC created
Match the year with the discovery: Years: 1952 1981 1998 2007 Discoveries: -human iPSC created -SCNT first performed -human embryonic stem cells isolated -mouse embryonic stem cells isolated
Mesencymal adult stem cells
Most current stem cell clinical trials in humans involve what type of stem cells?
Principle of Respect for Autonomy
Patients have autonomy over their health decisions and tissues, patients must understand the risks before they can consent, patients have autonomy over their health care and tissues (informed consent)
Fertilization Cleavage Blastulation Gastrulation Neurulation
Place the stages of embryogenesis that we discussed in their correct order, starting from the event nearest to the time of conception. Cleavage Fertilization Neurulation Gastrulation Blastulation
moving cells to another place in the organisms (or another organism's ) body, and determining if they assumed the identity of the donor or host tissue (also known as Chimeric animal models)
Prior to the 20th century, what techniques were used by experimenters to investigate the potency of different cell types?
false (Cell therapies, such as those that involve MSC, can offer therapeutic benefit by what are known as bystander effects- immunomodulation, growth-factor secretion, and by promoting angiogenesis)
T/F: Cell replacement is the only explaination for the beneficial effects of experimental neural stem cell based therapies
true
T/F: Compared to the United States, there is less debate and division over stem cell therapies in Eastern Asian nations
false
T/F: Due to the political controversy over stem cells, federal funding at the NIH has been reduced, and federal funds are no longer allowed to go to either hESC or fSC research.
Structure
The arrangement of parts in an organism to become a human life, formation of the nervous system (3-5 weeks, first neurons and possibility of sensation), embryo becomes fetus (8 weeks, all organs formed and start becoming functional)
Glasgow coma score of 3 Confirmed by second physician No activity (glucose uptake) in the cerebrum
The criterion for being declared brain dead encompass all of the following... (Select all that apply) No activity (glucose uptake) in the cerebrum Not making urine No heartbeat No activity (glucose uptake) in the brainstem Confirmed by second physician Glasgow coma score of 3
Hematopoietic; cancer
The only currently FDA approved stem cell therapies use _____ stem cells for treating _______
Clonality
The propensity of a cell to generate progeny that are identical to the parent cell
Viral vector
Use cell surface receptors to come inside the cell and release their RNA/DNA and the cell transcribes it and makes more, in retro - puts the DNA in for good! (integrates into host DNA), cell can sometimes turn off the transgene or not express at all, can be turned off/on to regulate MMLV-derived: -retro -only infects dividing cells -forever (integrates into DNA) -can put everything in 1 or multiple viruses, Lentivirus: -retro -infects ALL cells -forever (integrates into DNA) -transgene that can sometimes be turned on/off (e.g. DOX chemical required next to cell to transcribe) Adenovirus -non-integrating -infects ALL cells -causes the common cold
the zygote and the cells formed one or two divisions later
What cell can generate all cell types? embryonic stem cells trophoblasts the zygote and the cells formed one or two divisions later Both the zygote AND embryonic stem cells
placing cells in the 4 C refridgerator for long term storage
What is NOT a technique used in embryonic stem cell culture? passaging cells when they become too dense growing cells in a flask placing cells in the 4 C refridgerator for long term storage feeding cells a mixture of electrolytes, vitamins, and signaling molecules
All of the above
What is a reason to dismiss concerns over the possibility of human cloning in the immediate future? SCNT cannot recapitulate epigenetic effects on gene expression that occur during normal development SCNT tends to be inefficient each organism cloned seems to present unique challenges that do not generalize to other organisms All of the above
a neural stem cell
What kind of cell arrises from the ectoderm? a bone marrow stem cell a neural stem cell a placental cell a lung cell
a lung cell
What kind of cell arrises from the endoderm? a placental cell a bone marrow stem cell a lung cell a neural stem cell
a bone marrow stem cell
What kind of cell arrises from the mesoderm? a placental cell a neural stem cell a bone marrow stem cell a lung cell
Adult stem cells normally help the body replace tissues that get worn out
What statement about adult stem cell biology is the most accurate? Adult stem cells are more potent than embryonic stem cells Adult stem cell therapies are not researched because they are not considered to be as safe as embryonic stem cell therapies Adult stem cells normally help the body replace tissues that get worn out Adult stem cells cannot be cultured Adult stem cells can only be obtained through invasive surgeries requiring general anesthesia
they are simply "blank cells" that haven't expressed proteins yet
What statement about induced pluripotent stem cells (iPSC) is FALSE? they act like embryonic stem cells they can be made from skin cells, blood cells, and immune cells the process they are formed by is rather inefficient, with less than 1/1000 cells becoming iPSC they are simply "blank cells" that haven't expressed proteins yet
sox2, oct3/4, klf4, c-myc
What were the four genes used to reprogram the first mouse and human induced pluripotent cells?
They are all transcription factors
Which answer or answers best describe the genes that reprogram adult cells into a pluripotent state? They are all transcription factors They are all growth factor receptors They include NeuN and Nestin C-myc is required A and D only
companies must publish the results of clinical trials
Which of the following is FALSE? FDA regulation of health supplements differs from regulation on drugs and therapeutics Stem cell clinics in the U.S. can perform autogenic stem cell transplants for a wide-range of conditions without FDA approval because they are classified as surgery companies must publish the results of clinical trials privately run stem cell businesses can receive funding from charity organizations
Negative trial results are virtually never published, slowing progress
Which of the following is a common criticism of the FDA-regulated clinical trial model for approving treatments in the U.S.? Negative trial results are virtually never published, slowing progress The model only applies to small-molecule drugs, not cells The process is too quick and many therapies need to be recalled Most of the burden for bringing a new drug to market directly falls on the tax-payer because studies are largely funded by the NIH
determining efficacy of the treatment is an important goal
Which of the following would be FALSE with regards to a Phase 1 clinical trial? determining efficacy of the treatment is an important goal healthy subjects are used and small doses given determining how doses are tolerated is an important goal these are often conducted in an open-label design
These viruses are used to cause the expression of genes tied to tumor formation
Why do researchers emphasize caution when it comes to using cells that were reprogramed to iPSC using viruses in human therapies? These viruses are used to cause the expression of genes tied to tumor formation All viruses have to integrate into the genome to function and can cause mutations Genes activated by viruses cannot be controlled once they're in a cell The cells must come from allogeneic sources
c-myc is an oncogene, meaning that it promotes tumor formation
Why is c-myc not a good reprogramming factor for use in iPSC cells destined for transplant into humans?
Totipotent
a cell can become ALL cells in the human body that ever exist at any stage of development (e.g. zygote or morula) between 2-64 cell stage of development (divide a bunch first)
Lineage
actual fates that a cell will acquire (in vivo), family tree of what cells did in order to give rise to a particular cell type in vivo, not the same as potency (can vs. will)
Pluripotent
cells have MANY fates in that they can become many types of cells but not all cells, (e.g. embryonic stem cells)
Multipotent
cells have SEVERAL fates, (e.g. adult stem cells), often tissue specific
Biologics Licensing Application (BLA)
company can request this if a phase 3 clinical trial is successfully completed, request marketing approval, biological licence application (e.g. stem cells)
New Drug Application (NDA)
company can request this if a phase 3 clinical trial is successfully completed, request marketing approval, new drug application
Investigational New Drug Application (IND)
describe the results of animal research, clearly defines how the clinical trial studies will be conducted, the FDA reviews this and approves this then the theraputic moves on to a phase 1 clinical trial, can take years to get approved, application for clinical trial
Hayflick Limit
different for different types of cells, 40-60 for normal cells, 80-160 for stem cells, cells can be coaxed to divide even longer by introducing genes from cancer or viruses (transformed or immortalized cells), telomeres on the end of chromosomes keep DNA protected from degeneration and if shortened enough can no longer divide
Zygote
fertilized egg, totipotent, fusion of two haploid germ cells, typically occurs in the oviduct, the two cells fuse and their pronuclei then divide, after 30 hours (about a day) the pronuclei fuse and this divides into 2 diploid cells called blastomeres, if to part becomes 2 identical twins, do not get all DNA here (get mother's mitochondrial DNA later),
Morula
generated by cleavage: mitotic division of the zygote without an increase in size, 4-5 divisions or doublings, no significant growth, no increase in volume or weight, occurs along certain axes this is about 8-32 cells, DNA still hasn't been transcribed, (using RNA you started with), cells often remain totipotent for a good while during cleavage wherein others cease to be totipotent after a few divisions, totipotent stem cells in a shell called the zone pellucida
single-blind
patients do not know what treatment they are getting but researchers do
double-blind
patients do not know what treatment they are getting, researchers do not know what treatment they are administering/monitoring, best form of study
open label
patients know what treatment they are getting
Potential
possibility of becoming a life in the future, valued at conception (0-5 days after sex), implantation (7-10 days , pregnancy test detectable), when life outside the womb is possible (23-27 weeks, this is still valued because don't know if can live on their own but now separate from the other because can survive by itself, decision after this point generally to save the mother),
Principle of Non-commercialization
research is research, no profit can come of donated tissues, do NOT profit off of research!, do not buy and sell tissue/cells without patient knowing, donation vs buying and selling
Principle of Safety and Utility
testing and research is essential to establish safety, treatments should be effective, avoid fraudulent treatments, do not do human experiments but if you do so it has to be sage and effective!
Clonality
the condition of being identical to the parent cell, the degree of this exhibited by a cell is the degree to which self-renewal generates cells that are identical to the parent cell, can be influenced by cell intrinsic and extrinsic factors causing the cells to divide, clone cell efficiently, quickly and effectively, most somatic cells cultured have infinite ability to divide, double by mitosis or proliferate, stop dividing and eventually die,
Potency
the number of possible fates that a cell can aquire by differentiation (in vitro), what can the cell do? (put cell in embryo and see what it becomes), how many types of cells can a cell become, this decreases with age but remains in stem cells, defines types of stem cells,
Chimeric mice
these models (specifically) are used to demonstrate pluripotency, insert a cell with some genetic marker into a blastocyst, see what types of cells bear the genetic mark in the adult (often use a way to tag them), a pluripotent cell will contribute to all tissues 1920s experiment by Dr. Hilde Mangold showed that tissues of the early vertebrate embryos were pluripotent, if a certain area was removed from the embryo of one newt and placed into another area of a second newt, and entire body formed, right after blastocyst phase, spermann organizer (coordinates what things become by releasing signals),
Medical Tourism
those from developed countries who travel to developing countries for lower-priced medical treatments. The motivation may be for medical services unavailable or non-licensed in the home country There's a high global demand for (stem) cell-based therapies => this may lead some patients with chronic or end-stage disease to seek unproven (stem) cell treatments motivated by therapeutic hope; There is a worldwide proliferation of "stem cell" clinics!! => problematic b/c they supply unproven, untested, and potentially dangerous (stem) cell treatments => Differences in regulatory frameworks across different countries exacerbate the problem few cell-based therapies are standard of care or approved by regulatory agencies, high global demand for (stem) cell-based therapies, patients with chronic or end-stage disease will seek unproven cell treatments motivated by therapeutic hope, world-wide proliferation of "stem cell" clinics, supply unproven, untested, and potentially dangerous stem cell treatments, differences in regulatory frameworks across different countries exacerbate the problem
Principle of Justice
treat all with an equal amount of respect, fairness in the distribution of resources, application of laws, do things to subjects fairly and equally
iPSC that are undifferentiated
what cell type is considered to pose the highest risk for tumor formation when transplanted in vivo? ESCs that are undifferentiated ESC that have been allowed to differentiate iPSC that are undifferentiated iPSC that have been allowed to differentiate
