Totipotent cells are cells with unlimited potential, mostly recognised as the produced cells when the sperm meets the egg during fertilisation. Each time these totipotent cells divide, identical cells are created and may develop into a foetus, with the outer layer of cells forming the placenta. Thus, totipotency is the process whereby a stem cell can divide into a new individual.
After totipotent cells eventually specialise in the uterus, after the first few divisions, forming blastocytes or bundle of cells, they cannot give rise to the uterus and therefore cannot make a new organism by themselves. These cells are called pluripotent cells. They possess the flexibility to differentiate into any cell type in the body.
Essentially, totipotency can only be found in early embryos; each cell with the ability to form a complete new organism. Contrastingly, pluripotency can be found in the inner cell mass of the blastocyst where cells can form any cell type in the human body.
4) Compare the possible uses of Umbilical Cord Blood Stem Cells and Human Embryonic Stem Cells?
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It is hoped that umbilical cord blood stem cells can be used as a potential source of tissue for transplants. Blood can be obtained from a newborn baby's umbilical cord, rich in cord blood stem cells. In effect, these can be used to produce blood and immune system cells.
If in the future the baby needs the cells for any purpose, (having had the blood stored in a 'cord blood bank') it can be transferred back with no chance of rejection and hopefully act as an effective treatment by differentiating into a tissue or organ. It has already been used to treat patients who have undergone chemotherapy to destroy their bone marrow due to cancer or other blood-related disorders.
Human Embryonic Stem Cells are pluripotent cells collected from early blastocysts that maintain the ability to become any cell type that make up the human body (More than 200). Another significant feature of this cell type is its skill to divide indefinitely and maintain its undifferentiated state. This allows for unlimited numbers of identical and genetically characterised stem cells to be used for medical purposes.
In comparison to the umbilical cord blood cell, research shows predictions that embryonic cells may be able to be used for cardiac repair. Human embryonic cells, alongside several other cell types such as myoblasts and cardiac stem cells have been considered as possible treatment sources for repairing damaged heart tissue. Heart muscle repair with adult stem cells. This figure is divided into two panels, with each illustrating a possible means by which adult stem cells could help regenerate damaged heart muscle. On the left, a mouse heart is being injected with a syringe of green-labeled adult stem cells. Next, a magnifying glass shows a close-up of the damaged heart muscle cells (greyish-black) next to an area of healthy heart muscle (pink). Arrows indicate that the adult stem cells are intermingling with the heart muscle fibers. On the right, a mouse is shown being injected in the tail blood vessels with a syringe of pink human bone marrow stem cells. The magnifying glass in this panel again shows a close-up of the damaged heart muscle cells (greyish-black) next to an area of healthy heart muscle (pink). The pink human bone marrow stem cells intermingle with the heart muscle fibers and the text indicates that they induce new blood vessel formation in the damaged heart muscle and also cause proliferation of existing heart blood vessels.
What's more, even newer studies have indicated the possibility for human embryonic stem cells to be directed to form insulin-producing cells. These could be used in transplantation therapy for people with diabetes.
Clearly, both human embryonic stem cells and umbilical cord blood stem cells share many similarities. They each have the capability to assist with the treatment against diseases; cord stem cells used against cancerous bone marrow and embryonic cells used to fight diabetes and build up heart tissue. Moreover, both of the stem cells have to be transferred to achieve the desired outcome.
As a slight contrast, however, the stem cell type itself varies between the two. The umbilical cord blood stem cell is naturally a totipotent stem cell; present in the early stages of embryo development. It is able to produce all of the blood cells in the body (hematopoietic). On the other hand, the human embryonic cell is a pluripotent stem cell. It cannot divide into a new individual but can undergo directed differentiation to become any type of cell in the body, not just a blood cell.
5) "Whether the use of stem cells should be encouraged in society"
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Whether the use of stem cells in society should be encouraged is an argument that requires deep consideration into the ethical, moral and scientific factors that are involved. On one side, advocates tout its benefits with the chance of curing several of man's most dreaded diseases. However, the opposition argue that the destruction of human embryos defies all grounds of science and ethics.
The use of stem cells has many medical advantages that for many people are enough to rule out the moral argument. Due to their unspecialised nature, stem cells have the ability to effectively grow into muscle, bone, cartilage and tissue; just about every cell in the human body. With this property to differentiate and self-renew, it has presented medicine with an opportunity to investigate a treatment course for degenerative disorders and conditions like cancer, where there has otherwise been no known cure. For example, studies have shown human embryonic stem cells having the capability to undergo direct differentiation and form insulin producing cells; an effective therapy for people suffering with diabetes. Moreover,
Another advantage for the use of stem cells in medicine is its ability to prolong our lives and hinder the effects of aging. Stem Cell research has already discovered many cures to slow down the process of aging and more impressively, may offer a 'treatment' for aging altogether. An investigation towards this area in 2004 illustrated the possibility that adult stem cells, which deteriorate with age, could be rejuvenated with the correct use of biochemical cues. Trials with stem cells taken from patients have provided evidence to suggest that in future years; medicine will include the repair and renewal of aged stem cells.
However, research has not only showed positive and hopeful signs for a medical breakthrough using stem cells but many negative factors as well. A more recent research conducted showed stem cell therapy being used on heart-disease patients.