Recently, due to the isolation and culture of the first human pluripotent stem cell lines of the successful, persons with great surprise, in biomedical research, and opened up a Xinjiang territories. Human pluripotent stem cell line development worthy of people carrying out rigorous scientific investigation, to evaluate new therapies and prevention strategies and on ethical issues in open discussion. In order to be able to understand the importance of this discovery and related scientific, medical and ethical issues, first of all we have to the relevant terms and definitions to understand.
What are stem cells?
Stem cells have been cultivating irregularly differentiation and produce specialized cells. In normal human development environment, they are the best explanation. Human development begins at fertilization of the egg cell, resulting in a growth to the full potential of the single cell organisms, i.e. omnipotent of fertilized eggs. Fertilization in the first few hours, Zygote Division for identical totipotent cells. This means that if any one of these cells into the uterus in women are likely to develop into a fetus. In fact, when two totipotent cells were developed to separate genetic genotypes, i.e. There are identical twins. In about four days after fertilization, after several cycles of cell division, these totipotent cells begin specific, form a hollow ring of cells in group structure, called a blastocyst, embryo SAC by the outer cells and is located in the hollow sphere within the cell clusters (known as the inner cell group).
Outer cells to continue to develop, the formation of the placenta and fetus in the uterus of the other support organizations. Inner cell group of cells will continue to form the human development, the entire organization. Although the group can be formed within the cells of the body of all organizations, but they will not be developed as a single organism, because they could not form the placenta and intrauterine growth necessary to support the organization. These cells are the cells of the group within the pluripotency — they can produce many different types of cells, but not the fetal development all cell types. Because they are not the omnipotent nature, is not an embryo, not full development potential. If the cell is placed into the uterus in women, it does not develop into a fetus.
Pluripotent stem cells undergo further specific differentiation, development of special functions for participation in the formation of cell stem cell. As hematopoietic stem cell, it can produce red blood cells, white blood cells and platelets. Again such as skin stem cells, it can produce various types of skin cells. These more specific stem cells known as exclusively competent cells.
Stem cells on early human development are particularly important in children and adults can also be found exclusively competent cells. Give us the most well known one of stem cells, and haematopoietic stem cells, for example, hematopoietic stem cells exist in every child and adult bone marrow, also present in the circulation of the blood, but a very small number. In our entire lives, hematopoietic stem cells constantly to human blood cells: red blood cell supplements, white blood cells and platelets in a very crucial role. If no blood stem cells, we cannot survive.
Stem cell related terms
DNA: constitute gene DNA (deoxyribonucleic acid).
Gene (gene): located in a specific location on a chromosome DNA fragments, is a genetic function units. A gene may direct guidance function enzymes and protein synthesis.
Somatic cell (cell): in addition to egg or sperm outside the cell.
Somatic cell nuclear transfer (somatic cell nuclear transfer): somatic cell nucleus transfer to go nuclear egg cell process.
Stem cells (stem cells): a training can be conducted from time to time differentiation and produce specialized cells in the cell.
Pluripotent (pluripotent): differentiation of a variety of organizations.
Totipotent (supernormal): with unlimited differentiation potential. Totipotent cells to specialize, embryo and organization, the embryo and the late all embryo tissues and organs.
Multipotent (specially competent cells): Multipotent stem cells to differentiate into specialized competent cells, specifically Multipotent stem cells can differentiate into some type of cells, such as neural stem cells that can differentiate into all types of neurons; hematopoietic stem cells that can differentiate into red blood cells, white blood cells and other blood cells.
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