[A B C D E F G H I J K L M N O P Q R S T U V W X Y Z]

Anemia- A decrease in the number of red cells and, therefore, the hemoglobin concentration of the blood. This results in decreased ability of the blood to carry oxygen. Severe anemia can cause a pale complexion, weakness, fatigue, and shortness of breath on exertion.

Antibodies- Proteins that are made by B lymphocytes in response to foreign substances called antigens. For example, infectious agents like viruses or bacteria cause lymphocytes to make antibodies against them. In some case, the antibodies are protective and prevent a second infection. These antibodies can be used to identify specific cells and improve the classification of leukemia or lymphoma.

Antiglobulin Test- This laboratory procedure can identify antibodies on the surface of red cells of platelets. Patients with chronic lymphocytic leukemia and other lymphocytic malignancies may make antibodies to their own red cells or platelets. (auto or self-directed antibodies). These autoantibodies may lead to anemia of low platelet counts. The antiglobulin test can be used to recognize the presence of autoantibodies on blood cells.

Apheresis- The process of removing components of a donor's blood and returning the unneeded parts to the donor. This process makes it possible to remove desired elements from large volumes of blood. Platelets, red cells, white cells, or plasma can be removed separately.

Autologous Marrow (Stem Cell) Infusion-This technique, often referred to as transplantation, involves the harvesting of a patient's marrow of blood. The stem cells are usually frozen for later use. The patient is then given intensive therapy, and the stem cells are reinfused via an indwelling catheter. The blood of marrow may be obtained from a patient with a disease of the marrow ( for example, acute myelogenous leukemia) when in remission or when the marrow is not overtly abnormal ( for example, lymphoma requiring intensive therapy). The purpose of the procedure is to restore blood cell production from the preserved and reinfused stem cells after intensive therapy has severely damaged the patient's remaining marrow.

Basophils- A type of white blood cell that participates in certain allergic reactions.

Banding of Chromosomes- The staining of chromosomes with dyes that bring out or highlight bands or regions on the chromosome. The bands give the chromosomes more specific features, allowing individual distinctions to be made among them. This technique permits more precise identification of each of the 23 pairs of chromosomes.

Blast Cells- This term refers to the earliest marrow cells identified by the light microscope. Blasts represent about 1 percent of normally developing marrow cells. They are largely myeloblasts, which are cells that will develop into neutrophils. In the acute leukemia, blast cells similar in appearance to normal blast cells accumulate in large numbers, perhaps up to 80% of all marrow cells.

Bone Marrow- The bones are hollow and their central cavity is occupied by marrow. After puberty, marrow is most active in blood cell formation.

Chemotherapy- The use of chemicals to kill malignant cells. Side effects of chemotherapy are mouth sores, diarrhea, rashes, and hair loss.

Chromosomes- All normal human cells with a nucleus contain 46 structures called chromosomes. The genes are the principal structures that make up the chromosomes. The X and Y chromosomes determine our sex and are referred to as the sex chromosomes.

Clonal (monoclonal)- A population of cells derived from a single primitive cell. The cancers is the total accumulation of cells that grow from the single mutated cell.

Cultures- Samples of body fluid such as sputum, blood, urine, and swabs of the inside of the nose and throat, as well as rectum, use to determine the principal site of an infection.

Cycles of Treatment- The term designates an intensive, clustered period of chemotherapy. A treatment may be given for several days or weeks and represents one cycle. The treatment plan may call for two, three, or more cycles.

Cytogenetics- The process of analyzing the number and shape of the chromosomes of cells. The individual who prepares, examines, and interprets the number and shape of chromosomes in cells is called a cytogeneticist.

Cytokines- These are cell derived substance that are secreted by various types of cells and act on other cells to stimulate or inhibit their function. Cytokines that stimulate cell growth are sometimes referred to as "growth factors."

Differentiation- The process by which stem cells transform from cells without specific characteristics into cells of a single blood cell line. The red cells, platelets, neutrophils, monocytes, eosinophils, basophils, or lymphocytpes are formed by this process.

Eosinophils- A type of white blood cell that participates in allergic reactions and helps to fight certain parasitic infections.

Erythrocytes- A synonym for red cells.

Granulocytes- A type of white blood cells that has a large number of prominent granules in the cell body. Other blood cells have fewer granules. Neutrophils, eosinophils, and basophils are types of granulocytes.

Hematologist- A physician who specializes in the treatment of blood cell diseases. This person is either an internist, who treats adult, or a pediatrician, who treats children.

Hematopoiesis- This term describes the process of blood cell development in the marrow. It is a continuous process that is active normally throughout life.

Hepatomegaly- The term used to indicate enlargement of the liver.

Iliac Crest- The edge of the hip bone from which marrow is usually sampled for diagnosis of blood cell diseases.

Karyotype- The systematic arrangement of the 46 human chromosomes of a cell in 23 matched pairs by length from longest to shortest and other features.

Leukocytes- A synonum for white blood cells.

Leukopenia- A decrease below normal in the number of blood leukocytes.

Lymph nodes- Small structures that contain large numbers of lymphocytes; they are connected with each other by small channels called lymphatics. These nodes are distributed throughout the body.

Lymphocytes- A type of white blood cell that participates in the body's immune system.

Mitosis- The process by which a single cell divides into two cells. This process is also referred to as cell division, cell replication, or cell growth.

Monocytes- A type of white blood cell that assists in fighting infection. The macrophage is the monocytes in action and can combat infection in the tissues, or can serve other functions such as ingesting dead cells.

Multidrug Resistance- A characteristic of cells that makes them resistant simultaneously to the effects of several different classes of drugs.

Mutation- An alteration in a gene that results from a change (injury) to the DNA in a cell.

Neutropenia- A decrease below normal in the number of blood neutrophils, a type of white blood cell.

Neutrophils- The principal phagocyte cell in the blood. This blood cell is the main cell that combats infections.

Oncogene- A mutated gene that is the cause of a cancer.

Pancytopenia- A decrease below normal in the number of the three major blood cell types: red cells, white cells, and platelets.

Petechiae- Pinhead-sized sites of bleeding in the skin. This type of bleeding results from a low platelet count. They disappear gradually when the platelet count increases.

Phagocytes- Cells that readily eat microorganisms like bacteria or fungi and can kill them as a means of protecting the body against infection.

Platelets- Small cell fragments that stick to the site of blood vessel injury, aggregated with each other, and seal off the injured blood vessel to stop bleeding.

Platelet Transfusion- The transfusion of donor platelets is frequently needed to support patients treated for acute leukemia. The platelets are collected by apheresis.

Polymerase Chain Reaction (PCR)- A technique to expand trace amounts of DNA or RNA so that the specific type of the DNA or RNA can be determined.

Red Cells- Blood cells that contain hemoglobin, which binds oxygen and carries it to the tissues of the body. The red cells make up about 45 percent of the volume of the blood in healthy individuals.

Relapse- A return of the disease after it has been in remission following treatment.

Remission- Acomplete disappearance of a disease, usually as a result of treatment.

Resistance to Treatment- The ability of cells to live and divide despite their exposure to a drug that ordinary kills cells or inhibits their growth. This is the cause of refractory malignant disease, whereby a proportion of malignant cells resist the damaging effects of a drug or drugs.

Somatic Mutation- The alteration of a gene in the cells of a specific tissue causing the gene to become a cancer-causing gene or oncogene.

Spleen- An organ in the left upper portion of the abdomen just under the left side of the diaphragm. It is often affected in leukemia, especially the lymphocytic leukemias, lymphoma, and Hodgkin's disease. Enlargement of the spleen is referred to as "splenomegaly." Removal of the spleen by surgery is referred to as "splenectomy." Removal of the spleen can be done without ill effect since its function can be performed by other organs such as the lymph nodes and liver.

Stem Cells- These are primiive cells in marrow that are important inmaking red blood cells, white blood cellsm and platelets. Generally, the stem cells are found largely in the marrowm but some leave the marrow and circulate in the blood.The stem cells in blood can be collected, preserved by freezing and, later, thaqed and used for therapy.

Stem Cell Transplantation- This is a thchnique which was developed to restore the moarrow of patients who had lethal injury to that site. Such injury can occur because of primary marrow failur, destruction of marrow by disease, of intensive chemical of radiation exposures. AS first designated, the source of the reansplant was the marrow of a healthy donow who had the same tissue type (HLS type) as the patient. Usually, the source was a brother of sister.

Therapy- The curative treatment of leukemia, lymphoma, or myeloma is thought of in different phases. Induction therapy refers to the methods used to destroy visible leukemia cells in blod and marrow so as to favor a remission, which results in return of normal blood cells. Consolidation therapy refers to the additional treatment given after remission is induced. Often, high doses of drugs are used in several short periods of treatment. The goal is to further decrease the concentration of residual leukemia cells. The greater the reduction in leukemia cells, the higher the probability that natural defenses will suppress the sesease and result in a long-term remission.

Thrombocytopenia- A decrease below normal in the number of the blood platelets.

Tumor Suppressor Gene (antioncogene)- A gene that acts to prevent cell growth.If a mutation ocurs in this gene, it may make the individual more susceptible to the development of cancer in the tissue in which the mutation occurs.

White Blood Cells- A synonym for leukocytes, There are five types of white blood cells: neutrophils, eosinophils, basophils, monocytes, and lymphocytes.