Stem Cell Research Leukemia. By Pui-Man Lau. Word count: Approx Grade awarded June 2006: PASS

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1 Stem Cell Research Leukemia By Pui-Man Lau Word count: Approx 1200 Grade awarded June 2006: PASS Research Paper Based on Pathology lectures At VETSIX

2 Abstract This paper has been produced using general background information from lectures held at The Vetsix Conference 2005 and also personal research. Stem cell research is constantly growing and is leading to more possible ways to treat animals. I plan to look at the use of stem cells in treating leukemia which widely affects domestic cats as well as some wild felines, and the ethical issues surrounding it. Introduction Stem cells are the foundation cells for every organ, tissue and cell in the body. They can ultimately be programmed to perform any number of specialized tasks. Stem cells are undifferentiated, which means that they do not have a specific function yet. Under suitable conditions, stem cells begin to develop into specialized tissues and organs. Moreover, stem cells are selfsustaining and can replicate themselves for very long periods of time. These unique characteristics make stem cells very promising for supplying cells to treat debilitating diseases like Alzheimer's disease, cancer, Parkinson's disease, type-1 diabetes, spinal cord injury, stroke, burns, heart disease, osteoarthritis and rheumatoid arthritis. Nowadays, donated organs and tissues are often used to replace those that are diseased or destroyed. Unfortunately, the number of people needing transplants far exceeds the number of organs available. Stem cells offer the potential for supplying cells and tissues, which can be used to treat these various diseases. All human beings start their lives from a single cell, called the zygote, which is formed after fertilization. The zygote divides and forms two cells; each of those cells divides again, and so on. Later, about five days after conception, there is hollow ball of about 150 cells called the blastocyst. The blastocyst is smaller than a grain of sand and contains two types of cells, the trophoblast and the inner cell mass. Embryonic stem cells are the cells that make up the inner cell mass. As embryonic stem cells can form all cell types in an adult, they are referred to as pluripotent stem cells. Stem cells can also be found in very small numbers in various tissues in the adult body. For example, bone marrow stem cells are found in the marrow of the bone and they give rise to all specialized blood cell types. Adult stem cells are typically programmed to form different cell types of their own 2

3 tissue; they are called multipotent stem cells. Adult stem cells have not yet been identified in all vital organs. In some tissues like the brain, although stem cells exist, they are not very active, and thus do not readily respond to cell injury or damage. Scientists are now also exploring ways in which they can induce the stem cells already present to grow and make the right cell types to replace the damaged ones. 3

4 Discussion Leukemia is a disease characterized by the formation of abnormal numbers of white blood cells, for which no certain cure has been found. Leukemia is also conditions characterized by the transformation of normal blood-forming cells into abnormal white blood cells whose unrestrained growth overwhelms and replaces normal bone marrow and blood cells. Leukemias are named according to the normal cell from which they originate, such as Lymphocyte Leukemia. Lymphocyte Leukemia is where a Lymphocyte cell is transformed into a Leukemia cell. Another example of Leukemia is Myelocytic or (Granulocytic Leukemia). This forms when a Myelocytic cell is changed or transformed into a Leukemia cell. Different Leukemia's are located in the microscope and by how much protein they contain. These Leukemia's are usually very severe and need treatment right away. The danger to the patient lies in the growth of these abnormal white cells, which interfere with the growth of the red blood cells, normal white blood cells, and the blood platelets. The uncontrolled growth of the abnormal white cells produces a tendency to unstop bleeding, the risk of getting serious infection in the wounds, and a very small possibility of obstruction of the blood vessels. Treatment of these Leukemias include chemotherapy with alkylafing agents, or antimetabodies that suppress the growth of abnormal white cells. Another treatment of some kind would be the x-ray or the administration or radioactive substances, or radiophosphorus, may be used. After treatment these diseases may last for many years. Age of the person diagnosed with Leukemia does play an important part in how that individual responds to any treatment. The older the person the less response he may have to treatment. Leukemia in Animals white blood cells is much less common as Leukemia in humans white blood cells. Today's treatment mostly includes chemotherapy and or bone marrow transplantation supportive care, where transfusions of blood components and prompt treatment of complicating infections, is very important. Ninety percent of children with Acute Lymphocyte Leukemia have received chemotherapy and fifty percent of theses children have been fully cured of Leukemia. Treatment of AML or Acute Myeolcytic Leukemia is not as successful but has been improving more and more throughout the 1990's. 4

5 Scientists that study the cause of Leukemia have not had very much success lately. Very large doses of x-rays can increase the efficacy growth of Leukemia. Chemicals such as Benzene also may increase the risk of getting Leukemia. Scientists have tried experiments on Leukemia in Animals by transmitting RNA into the body of the Animal. Interpretation of these results in relation with human Leukemia is very cautious at this time. Studies have also suggested that family history, race, genetic factors, and geography may all play some part in determining the rates of growth of these Leukemias. Stewart Alsop is an example of Acute Myeoblastic Leukemia, or AML. On the day of July 21, 1971 Stewart was made aware of some of the doctors suspicions due to his bone marrow test. He was told by his doctor in Georgetown that his marrow slides looked so unusual that he had brought in other doctors to view the test and they could not come to an agreement so they all suggested that he take another bone marrow exam. The second test was known to be "hypocelluar" meaning that it had very few cells of any sort, normal of abnormal. The Georgetown doctors counted, about fourty-four percent of his cells were abnormal, and he added, with a condor that he later discovered characteristics. "They were ugly-looking cells." Most of them looked like Acute Meyoblastic Leukemia cells, but not all some of them looked like the cells of another kind of Leukemia, Acatymphoblastic Leukemia, and some of them looked like the cells of still another kind of bone marrow cancer, not a Leukemia, it is called Dysprotinemia. And even the Myeloblastic cells didn't look exactly like Myeloblastic cells should look. Stewart has been treated with chemotherapy and is still living today but he doesn't have very much longer to live. 5

6 Conclusion Most ethicists don t consider a blastocyst to be a person. An argument can also be made that the blastocyst is not destroyed, since the cells that were destined to become the embryo are exactly the stem cells that are cultured. Since these cells are still alive, and since they are still in an undifferentiated state, in what sense has the blastocyst been killed? 6

7 References