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Stem Cells By Sugandha Srivastav.

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1 Stem Cells By Sugandha Srivastav

2 What is a stem Cell? Stem Cells are unspecialized cells that renew themselves for long periods through cell division. These unspecialized cells can divide and differentiate into specialized cells in our body. They do this by activating the genes that cater the specialized cell. All cells in our body originated from stem cells, thus the name‘stem’. * Muscle cells, nerve cells, blood cells all do not replicate themselves, so it is obvious that there is something else that is producing them. For example, we all know that blood cells are made in bone marrow but do we know how? If we take a closer look at our bone marrow we’ll see the presence of many unspecialized cells, stem cells, waiting for the signals to tell them to differentiate.

3 How Do They Do it? Like mentioned before, when a stem cells receives the right signals it produces specialized cells. This happens because some of the signals enter the nucleus of the stem cell and activate certain genes that result in the production of specific proteins that make the stem cell look, act and actually become the specialized cell they are supposed to be.

4 Types of stem Cells Early Embryonic Stem Cells: After fertilization the zygote divides to produce a group of stem cells that are totipotent-meaning they can differentiate into any kind of specialized in our body. This group of cells is called an embryo. Blastocyst Embryonic Stem Cells: Seven days after fertilization the embryo form a hollow ball-like structure called a blastocyst which contains stem cells that are pluripotent- meaning that they can differentiate into most kind of specialized cells. Fetal Stem Cells: During the eight week the embryo is called a fetus and has developed a human-like form. Stem cells in the fetus are responsible for the development of all tissues before birth. These fetal stem cells are like blastocyst embryonic stem cells pluripotent. Umbilical cord stem cells: The umbilical cord is what transports nutrients, oxygen etc. from the placenta to the fetus. The stem cells in the blood of this cord are genetically identical to the newborn child. These stem cells are multipotent-meaning they can differentiate into only a limited number of specialized cells. Adult stem cell : Adult stem cells are present in infants and children as well. These stem cells reside in already developed tissues to direct growth and maintenance throughout life. Like umbilical cord stem cells, adult stem cells are multipotent.

5 What is their Significance?
Stem cells on their own do not have a specialized job for example: a group of stem cells cannot function together to make our heart beat. However, a stem cell is like a neutral cell waiting to divide when there needs to be growth or repair. All deaths are caused due to growth and repair problems. For example, if a person has Parkinson’s disease their dopamine producing neurons will degenerate. We know that neurons themselves do not divide to produce more neurons but we do know that stem cells are the cells from which all specialized cells come. So we can transplant some of these cells into the patient so that they differentiate and produce a healthy set of dopamine producing neurons. This is the goal of stem cell therapy-to repair damaged tissue that can’t heal itself. It is useful to society as it has the potential to greatly increase the life expectancy of people around the world.

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7 Technological Link Stem Cell Therapies today:
Even though stem cell science is quite new, a few stem cell therapies are being used routinely to cure diseases. Adult stem cells transplant: Bone Marrow stem cells. Used to treat leukemia, various types of blood disorders and some types of cancer. Adult stem cells transplant: Peripheral Blood stem cells. These are the few stem cells that are present in the blood as opposed to the bone marrow. They can be obtained from drawn blood which makes them more readily available. They are used to treat the same disorders as bone marrow stem cells. Umbilical Cord Blood Stem cell transplant: Umbilical cord blood stem cell transplants are less prone to rejection than either bone marrow or peripheral blood stem cells. This is probably because the cells have not yet developed the features that can be recognized and attacked by the recipient's immune system. Also, because umbilical cord blood lacks well-developed immune cells, there is less chance that the transplanted cells will attack the recipient's body, a problem called graft versus host disease.

8 Stem Cell Therapies In The Future (Potential)
Researchers and physicians are working to design stem cell therapies that Are more effective, and Reduce the invasiveness and the risk to patients The stem cell therapies used today rely on transplanted stem cells from a donor. This increases the risk of the recipient’s body rejecting the stem cells or graft versus host disease. In the future it may be possible for a patient use a sample of their own stem cells to repair tissue. This is the aim of stem cell therapies in the future. This can be done by: Collecting healthy adult stem cells from a patient and manipulating them in the laboratory to create new tissue. The tissue would be re-transplanted back into the patient's body, where it would work to restore a lost function. Therapeutic cloning, might enable the creation of embryonic stem cells that are genetically identical to the patient. One less invasive way to achieve this goal would be to manipulate existing stem cells within the body to perform therapeutic tasks. For example, scientists might design a drug that would direct a certain type of stem cell to restore a lost function inside the patient's body. This approach would eliminate the need for invasive surgical procedures to harvest and transplant stem cells.

9 Stem cells have the potential to treat:
Parkinson's and Alzheimer's diseases, spinal cord injury, stroke, burns, heart disease, diabetes, osteoarthritis and rheumatoid arthritis –to name a few.

10 Problems and Questions
Theoretically stem cell therapy may sound easy: transplant the stem cells into the damaged area and direct them to grow new healthy tissue; but in practice many problems may arise such as: What are the signals that make stem cells differentiate? How long would stem cell therapy last-would the newly differentiated stem cells work for as long? Compatibility There is the possibility of embryonic stem cells developing into tumors as they are designed to continuously divide and differentiate, so how exactly do we control their growth?

11 Stem Cell Ethics Stem cell research comes with its share of ethical issues. For example: Do embryonic stem cells represent human life? Is it morally correct to destroy them for research and therapies? View 1: Yes it is since the embryonic destruction can save lives and destroying an embryo is not the same as killing a living human-being. An embryo is merely a developing ‘life’. View 2: No it isn’t because it interferes with laws of nature. What is the point of destroying one life to just save another? Should frozen embryos through vitro fertilization be used to create stem cells? View 1: Yes, since it is for a good purpose. View 2: No, since it is unnatural. Religion often plays a role in these debates as some people think that stem cell research will lead people to playing the role of “god”.


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