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27 Cards in this Set
- Front
- Back
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What are stem cells, and why are they important?
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Stem cells have the potential to develop into many different cell types
They are thought to reside in a specific area of each tissue of an organism called a stem cell niche. - embryo - adult - iPS |
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What are the unique properties of all stem cells?
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All stem cells - regardless of their source - have three general properties:
- they are capable of dividing and renewing themselves for long periods - they are unspecialized - they can give rise to specialized cell types |
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Which stem cells give rise to all the types of blood cells?
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Hematopoietic stem cells
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Which stem cells give rise to a variety of cell types like osteocytes, chondrocytes, adipocytes, and other kinds of connective tissue cells?
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Mesenchymal stem cells
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Which stem cells in the brain give rise to its three major cell types neurons, astrocytes and oligodendrocytes?
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Neural stem cells
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Which stem cells give rise to several cell types like absorptive cells, goblet cells, paneth cells, and enteroendocrine cells?
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Epithelial stem cells
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Which stem cells occur in the basal layer of the epidermis and give rise to keratinocytes?
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Skin stem cells
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What are embryonic stem cells?
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- embryonic stem cells are derived from embryos that develop from eggs that have been fertilized in vitro
- they can remain undifferentiated (unspecialized). |
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Testing whether the human embryonic stem cells are pluripotent by:
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1) allowing the cells to differentiate spontaneously in cell culture
2) manipulating the cells so they will differentiate to form cells characteristic of the three germ layers 3) Injecting the cells into a mouse with a suppressed immune system to test for the formation of a benign tumor called a teratoma |
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What are adult stem cells?
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An adult stem cell is thought to be an undifferentiated cell, found among differentiated cells in a tissue or organ that can renew itself and can differentiate to yield some or all of the major specialized cell types of the tissue or organ.
The primary roles of adult stem cells in a living organism are to maintain and repair the tissue in which they are found. |
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What are induced pluripotent stem cells?
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Induced pluripotent stem cells (iPSCs) are adult cells (like fibroblasta) that have been genetically reprogrammed to an embryonic stem cell–like state by being forced to express genes and factors important for maintaining the defining properties of embryonic stem cells. Although these cells meet the defining criteria for pluripotent stem cells, it is not known if iPSCs and embryonic stem cells differ in clinically significant ways.
Human iPSCs also express stem cell markers and are capable of generating cells characteristic of all three germ layers. |
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What are the similarities and differences between embryonic and adult stem cells?
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- Embryonic stem cells can become all cell types of the body because they are pluripotent.
- Adult stem cells are thought to be limited to differentiating into different cell types of their tissue of origin. |
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Totipotent/Omnipotent
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ability to give rise to all the cell types of the body plus all of the cell types that make up the extraembryonic tissues such as the placenta.
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Multipotent
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ability to develop into more than one cell type of the body.
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Pluripotent
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ability to give rise to all of the various cell types of the body. Pluripotent cells cannot make extra- embryonic tissues such as the amnion, chorion, and other components of the placenta.
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Teratoma
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A multi-layered benign tumor that grows from pluripotent cells injected into mice with a dysfunctional immune system.
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Prenatal Diagnosis (PND)
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(pränatal = vor der Geburt) bezeichnet Untersuchungen des Embryos und der Schwangeren während der Schwangerschaft.
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Ziele der PND?
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Erkennung von:
- Chromosomenanomalien - Erbkrankheiten aufgrund gezielter DNA Analyse - Neuralrohrdefekt - Geschlechtsbestimmung |
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Preimplantation Diagnosis (PID)
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Preimplantation diagnosis (PID) allows direct analysis of the genetic makeup of a developing embryo by extraction and examination of individual blastomeres.
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Polar body diagnosis (PBD)
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a new diagnostic method for the indirect genetic analysis of oocytes, which is carried out as part of in vitro fertilization. The biopsy of polar bodies is technically demanding and cannot be adopted uncritically in routine practice, in the absence of robust data to support this laboratory procedure.
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PBD and PID
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Can only be performed as part of in vitro fertilization (IVF) therapy. The procedures allow the demonstration of numerical chromosome maldistributions (aneuploidies), translocations, and monogenic diseases – detection of maternally inherited diseases only!
These methods have the goal of improving the success rates of assisted reproduction and of preventing pregnancies that lead to the birth of severely ill children. |
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How successful is in vitro fertilization?
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The success rate of IVF clinics depends on a number of factors including patient characteristics and treatment approaches. It is also important to understand that pregnancy rates are not the same as live birth rates. In the United States, the live birth rate for each IVF cycle started is approximately:
30 to 35% for women under age 35 25% for women age 35 to 37 15 to 20% for women age 38 to 40 6 to 10% for women age over 40 |
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What are the risks associated with in vitro fertilization?
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- Ovarian Hyper stimulation Syndrome
- Laparoscopy and anesthesia - bleeding, infection, and damage to the bowel, bladder, or blood vessel. - chance of a multiples pregnancy and premature delivery - Psychological stress and emotional problems |
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How many embryos should be created or transferred?
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- no more than four embryos per IVF cycle will yield optimal results.
- more than four is believed to result in excess numbers of multiple pregnancies, increasing the possibility of additional complications. - four embryos instead of only one or two increases the probability that pregnancy will occur. |
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What is cloning?
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- DNA Cloning
- Reproductive Cloning - used to generate an animal that has the same nuclear DNA as another currently or previously existing animal. - Therapeutic Cloning - production of human embryos |
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Can organs be cloned for use in transplants?
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- Therapeutic cloning
- can be used to generate human stem cells or tissues and organs for transplants - Xenotransplantation - the creation of genetically modified pigs can produce organs suitable for human transplants |
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What are the risks of cloning?
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- expensive and highly inefficient
- unclear long-term survival - genomes are compromised - genetic imprint of DNA from a single donor cell can lead to developmental defects |
