Advantages and disadvantages of different types of communication channels,lottery ticket poker game movie,communication quotes john wooden,watches 24 seven - Tips For You

Filter: All types Articles Slideshows Videos Sort: Most relevant Most popular Most recent No articles available No slideshows available No videos available Difference Between Managerial Economics & Microeconomics How Much Does an Insurance Broker Earn? Slideshare uses cookies to improve functionality and performance, and to provide you with relevant advertising. Advantages andDisadvantages of 3 Types of Businesses By: Shikari Martin December 7, 2011 Entrepreneurial Ventures Mrs. In the last few years, stem cell research has become the latest buzz in the popular media as well as the scientific world.
The following chapter aims to explain the science behind stem cells and their potential to treat HD. Most of the cells that make up the organs and tissues of the body are highly specialized for their specific jobs. If mature specialized cells cannot leave “children” behind when they die, how does your body make new cells? In more formal terms, a stem cell is a special kind of cell that has the ability to divide for indefinite periods of time and to give rise to the mature, specialized cells that make up an organism. Embryonic stem (ES) cells: ES cells are taken from the very early stages of embryo development and can give rise to all of the cells of the human body, except the placenta and other supportive tissues in the womb. Adult stem cells: Adult stem cells are found in the tissues of a fully developed child or adult and can only produce a limited number of cell types. These three types of stem cells are easiest to understand in a discussion of human development. Embryonic stem cells, which are also pluripotent, are isolated directly from the inner cell mass at this blastocyst stage.
Five to 10 weeks after fertilization, the growing embryo, now called a fetus, develops a region known as the gonadal ridge.
Embryonic germ cells are isolated from these primordial germ cells of the 5- to 10- week old fetus. As the human fetus continues to develop, pluripotent stem cells specialize into stem cells that are geared for specific tissues. While all three types of stem cells discussed above (ES cells, EG cells, and multipotent stem cells) are found in the developing human, only multipotent stem cells are found in children and adults. On the most fundamental level, stem cells are used to study the early events of human development. Currently, animal models are used to test drug safety and efficacy and to screen potential toxins. At first glance, embryonic stem cells, embryonic germ cells, and adult stem cells all present similar possibilities for scientific research. However, stem cell research is controversial, as most of the stem cell lines available today are derived from embryos or fetuses. The red blood cell, for example, is specifically crafted to carry oxygen from the lungs to the tissues. In fact, most cells lead very standard lives – they grow up, do the same job every day, and then eventually retire and pass away. A stem cell is uncommitted and remains uncommitted until it receives a signal to differentiate (become a specialized cell).



Human development begins when a sperm fertilizes an egg and creates a single cell, known as a zygote, which has the potential to form an entire organism. In 1998, researchers first isolated ES cells from human embryos that were obtained from in vitro fertilization clinics. The gonadal ridge contains the primordial germ cells, which will eventually develop into eggs or sperm.
For example, they become blood stem cells (which produce blood cells) or skin stem cells (which produce skin cells).
This research may one day explain the cause of birth defects and help devise new approaches to correct or prevent them.
Transplantation ResearchStem cells may hold the key to restoring many vital bodily functions by replacing cells lost in various devastating diseases.
Genetic Engineering ResearchStem cells could be used as a vehicle for delivering genes to specific tissues in the body. Animal models, however, cannot always predict the effects that a drug or toxin may have on human cells. Chromosomal Abnormality TestingStem cells might also be used to explore the effects of chromosomal abnormalities in early human development. They are all stem cells, after all, and therefore share some key characteristics and hold similar potential.
A comparison can be made with today’s society where most workers are trained to perform a specific trade. With every replication, the stem cell produces one new stem cell and one new specialized cell. These specialized stem cells are said to be multipotent, meaning they can give rise to many, but not all, types of cells. Unlike other stem cells, adult stem cells are only found in specialized tissues and can only give rise to the specialized cell types that make up that tissue.
Also, research on the genes and chemicals that control human development may help researchers manipulate stem cells to become specialized for transplantation or genetic engineering.
Many diseases and disorders, such as Huntington’s disease, disrupt specific cellular functions or destroy certain tissues in the body. The goal is to add genes to stem cells that would then coax the stem cell to differentiate into a specific cell type or force the stem cell to produce a desired protein product.
Therefore, if human stem cells can be used to generate cells that are important for certain drug or toxin screenings, these cells may offer a safer, more reliable test by mimicking a more realistic human environment. As a result, we might be able to understand and monitor the development of early childhood tumors, many of which are embryonic in origin. For example, they all have the ability to self-replicate for indefinite periods of time in the human body and can give rise to specialized cells. The days of the generic fix-it man are gone; instead, the electrician, the plumber, and the cable guy fill specific niches. They are mature cells that have characteristic shapes and are committed to performing specific functions (See Figure 1).
About 24 hours after fertilization, the zygote divides into two identical totipotent cells, and is now known as an embryo.


Currently, adult stem cells have been found in the bone marrow, blood, blood vessels, skeletal muscle, skin, lining of the digestive track, dental pulp of the tooth, liver, pancreas, cornea and retina of the eye, and brain. The goal, therefore, is to coax stem cells to develop into the desired specialized cells, which can then be used as a renewable source of replacement cells or tissues.
Currently, researchers are trying to use specialized cells derived from stem cells to target specific cancer cells and directly deliver treatments that could destroy them.
The overall purpose behind research with all types of stemm cells, therefore, is very similar.
About five days after fertilization and after several cycles of cell division, these cells begin to specialize and form a hollow sphere, called a blastocyst.
It has also been shown that all three cell types can be isolated from other cells and kept in a specific laboratory environment that keeps them unspecialized.
The blastocyst has an outer layer of cells that make up the shape of a sphere and a cluster of cells, known as the inner cell mass, inside the sphere. Instead, a stem cell remains uncommitted until it receives a specific signal to divide and produce one of the various specialized cells. Upon experimentation, it has also been shown that all stem cell types will replicate and specialize when transplanted into an animal with a lowered immune system. It's bad if informal communication would be a faster or easier method of resolving your issue. The inner cell mass cannot form an organism on its own, however, because it is unable to produce the placenta and the other supporting tissues necessary for development in a woman’s uterus. Homing provides hope that the transplantation of stem cells will be a clinically useful procedure. Therefore, the inner cell mass cells are said to be pluripotent, meaning they have the potential to give rise to most of the tissues required to produce an organism. In other words, they can give rise to all the cells of the human body, excluding the supportive tissues used in the womb. However, it can be a better way to resolve issues that don't benefit from getting up in a formal resolution process.
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Faxes can also become easily lost, especially if you work for a large business where these messages come through constantly. However, going over a great deal of written information may require having documents in front both the caller and the receiver -- face-to-face meetings are better for this. Depending on the mode of travel, however, it can take a while before reaching the recipient.



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