A2:a functional variant of adult hemoglobin, usually present in small quantities. Composed of two alpha globin chains and two delta globin chains. Elevated slightly in patients with beta thalassemia trait who are not iron or vitamin deficient. [close window] affinity: an attractive force between substances or particles that causes them to enter into and remain in chemical combination [close window] allele: any alternate form of a gene that can occur at any single locus on a chromosome. All individuals inherit one allele from each parent, but there may be numerous different alleles for a locus (protein coding area) in the world's population. Some alleles are advantageous and predominate, while others are not a occur less commonly. [close window] alloimmunization: production by an individual of antibodies against constituents of the tissues of others of his own species (as when transfused with blood from one belonging to a different blood group). In hematology, specifically implies a blood recipient who has made antibodies to a minor blood group antigen such as Kell, E or C. This can be avoided or decreased by transfusion with phenotypically- matched blood that is crossmatched for both major (A,B,O) and minor antigens. [close window] amniotic fluid: the fluid in the uterus that surrounds the fetus that contains fetal cells; testable by amniocentesis for chromosomally inherited diseases. The fluid itself can also be tested for biochemicals that might indicate risk for fetal disease. [close window] anaphylaxis: the immediate immunologic (allergic) reaction characterized by contraction of smooth muscle and dilation of capillaries. This leads to hypotension and wheezing (broncho-constriction) with difficulty breathing and hypotensive shock in severe cases. [close window] antigen: (also immunogen) any substance that can induce the immune system to mount an immune response, which can be of cellular nature, or as immunoglobin production as seen in bacterial infections and allergic reactions. At first exposure to an antigen, the immune system may not react but will be primed and 'remember' the antigen. The second encounter is usually more vigorous and can lead to anaphylaxis. [close window] calcium: an element that is essential to life. Besides being the major constituent of bone it is a messenger ion that regulates cell membrane permeability and is essential for muscle contraction [close window] catheter: a thin hollow tube used for insertion into vessels or body cavities usually to permit injection or withdrawal of fluids [close window] cholelithiasis: a medical term for gallstones [close window] desferoxamine: the only safe drug used to chelate iron; commonly known by its brand name of Desferal [close window] diaphoresis: perspiration, esp. profuse perspiration artifically induced [close window] diathesis: a constitutional predisposition toward a particular disease state or condition [close window] dyspnea: difficult or labored breathing [close window] electrophoresis: a method used to separate hemoglobin in the identification and diagnosis of hemoglobinopathies [close window] elliptocytosis: an abnormality in of blood production in which there is a large percentage of elliptically-shaped red cells, often associated with hemolytic anemia. [close window] engraft: to successfully have transplanted bone marrow or other tissue from donor to recipient. When a bone marrow transplant is successful, the marrow is said to have 'engrafted.' An allograft is engraftment between different individuals (technically of the same species). [close window] endocrine: This term applies to organs whose function is to secrete active biochemicals into the blood circulation that effects other distant organs. Usually there is a feed-back system that turns the secreting off when the desired effect has occurred. [close window] erythema: redness of the skin due to capillary dilation; this can indicate allergic reaction or infection [close window] erythrocytosis: an increase in the number of red cells in the blood, esp. in response to a stimulus such as anemia [close window] erythron: the total mass of circulating red blood cells, and that part of hematopoietic tissue from which they are derived [close window] exon: a portion of DNA that codes for a section of the mature messenger RNA (mRNA) from that DNA, and is therefore expressed or "translated" into protein at the ribosome [close window] exogenous: derived or developed from outside the body; originating externally. [close window] extramedullary hematopoiesis: red blood cell production outside the vertebrae. Red blood cells are derived from the stem cells in the bone marrow throughout the body. When individuals become severely anemic, there is not enough space in the ctive bone marrow to produce hemoglobin, and the body begins to make blood outside the bone marrow: in the spleen, liver, and sometimes outside the vertebrae, which can compress the spinal cord, leading to paralysis [close window] erythorpoiesis:production of red blood cells [close window] F: Fetal hemoglobin, present in extremely small quantities in regular adult blood. Composed of two alpha globin chains and two gamma globin chains. Will be elevated in patients with beta thalassemia trait. [close window] fava bean: large bean usually eaten boiled, sauteed or deep fried as a snack that can cause rapid hemolysis in Hgb H and H-CS patients, and therefore should be avoided [close window] febrile: feverish; to have an elevated body temperature [close window] fulminant: occuring suddenly, with lightning-like rapidity, and with great intensity or severity [close window] gene: a functional unit of heredity which occupies a specific place (locus) on a chromosome, is capable of reproducing itself exactly at each cell division, and directs the formation of an enzyme or other protein [close window] hemochromatosis: A disorder of iron metabolism characterized by excessive absorption of ingested iron, saturation of iron-binding protein, and deposition of hemosiderin in tissue, particularly in the liver, pancreas, and skin; cirrhosis of the liver, diabetes (bronze diabetes), bronze pigmentation of the skin, and eventual heart failure may occur. [close window] hemolysis: alteration, dissoultion, or destruction of red blood cells in such a manner that hemoglobin is liberated. The spleen normally filters the blood and removes abnormal red blood cells. If most cells are normal, the amount of hemoglobin released is easily metabolized by the liver and recycled by the body. If there are large numbers of abnormal red cells, the liver metabolizes the hemoglobin to bilirubin in quantities too great to be quickly recycled and jaundice results. [close window] hemorrhage: blood loss from the circulation. Bleeding can be external as in damage to the skin or internal as in trauma to the spleen. Internal hemorrhage is diffic [close window] hemosiderosis: excessive deposition of hemosiderin in bodily tissues. Hemosiderin is a molecule the body produces to sequester excess iron in a form that is inert. Hemosiderin can be metabolized to release the iron in response to anemia. [close window] hepatic vein: major blood vessel leaving the liver [close window] heterozygous: having different allelic genes at one locus. People who inherit two different alleles, one from each parent, are heterozygotes. Individuals who have thalassemia can inherit a different thalassemic gene from each parent and be heterozygotes, or inherit the same gene from each parent and be homozygous for that mutation. Both of these combinations can cause thalassemia disease, though homozygotes are more likely to have severe disease.[close window] HLA: human lymphocyte antigens; system designation for the gene products of at least four linked loci and a number of subloci on the sixth human chromosome which have a strong influence on human allotransplantation, transfusions, and certain disease associations (see antigen) [close window] homozygous: having identical genes at one or more loci (see heterozygous) [close window] hyperbilirubinemia: an abnormally large amount of bilirubin or yellow bile pigment in the circulating blood, resulting in clinically apparent icterus or jaundice when the concentration is sufficient [close window] hypercoagulability: excessive tendency for blood to coagulate, or become thickened and viscous, jelly-like, or solid. This can be due to an inherited loss or decrease in anticoagulant proteins or can occur in some disease processes. [close window] hypersplenism: any condition in which the cellular components of the blood or platelets are removed at an abnormally high rate by the spleen [close window] hypertension: abnormally high blood pressure [close window] hypochromia: in anemic persons, the percentage of hemoglobin in the red blood cells is less than the normal range, resulting in a paler appearance of red blood cells under the microscope [close window] hypogonadism: inadequate gonadal function, as manifested by deficiencies in production or secretion of gonadal (sexual) hormones. This is manifest by absence of secondary sexual characteristics such as body hair and breast development [close window] hypotension: abnormally low blood pressure [close window] hypoxia: a deficiency of oxygen reaching the tissues of the body [close window] icterus: another term for jaundice [close window] IgA: a class of immunoglobulins found in external bodily secretions (such as tears, saliva and sweat); a deficiency of this immunoglobin can be a cause of transfusion reactions. [close window] IgG: a class of immunoglobulins that include the most common antibodies circulating in the blood of higher vertebrates and are active esp. against proteins foreign to the body such as those found in bacteria. There are four subclasses of this immunoglobin [close window] index: a ratio or other number derived from a series of observations and used as an indicator or measure of a condition, property or phenomenon [close window] in vitro fertilization: fertilization of the woman's egg in a laboratory dish, after which the zygote is transferred into the woman's uterus and develops normally [close window] jaundice: a yellowish staining of the skin, the whites of the eyes and deeper tissues caused by an increased presence of bilirubin (bile pigments) in the plasma of the blood. This can be a result of excessive breakdown of red blood cells or liver disease such as hepatitis (also called icterus). [close window] leukocytes: all the white cells including: neutrophils, lymphocytes, eosinophils, basophils, and monocytes. [close window] leukocytosis: any condition in which the number of leukocytes or white cells in the circulating blood is abnormally high; a white cell count of 10,000 or more per cubic millimeter. This is a non-specific finding. Generally when there is an increase in red cell production, the white cell count is elevated. If there are many immature red blood cells present in the circulation, the white cell count as done by a machine is elevated. A 'corrected white count' is then done manually with a microscope. [close window] leukopenia: any condition in which the number of leukocytes or white cells in the circulating blood is less than normal, the lower limit of which is generally regarded as 2000-4000 per cubic millimeter. When some medications such as alpha interfuron or hydroxyurea are given, the white cell count can be lower than these values. In elevating immune function against bacteria, the absolute neutrophil count is used to determine whether these medications should be temporarily discontinued [close window] marrow: the part of the bone where the red and white cells are produced. In normal adults there is a fat in the bone marrow; in persons with anemia, the boen marrow is completely filled primarily with red blood cell precursors. [close window] maxillary hyperplasia: an increase in the number of cells, excluding tumor formation, in the maxilla (upper jaw bone), whereby the bulk of the maxilla is increased [close window] MCV: mean corpuscular volume; volume of the red blood cell. It si reduced is some anemias such as iron deficiency anemia and increased in other anemias such as vitamin B12 deficiency. [close window] megaloblast: a large erythroblast (precursor to a red blood cell) that appears in the blood during anemia [close window] microcytosis: decrease in the size of red blood cells; normal range for adults is 80-99 fL. This is an indication of iron deficiency or other anemia (such as thalassemia) [close window] mRNA: messenger ribonucleic acid; the molecule that carries the message of DNA to the site of protein production in a cell [close window] neonate: a newborn infant [close window] osteoporosis: reduction of the quantity of bone or atrophy of skeletal tissue; results in thin, brittle bones that fracture easily and do not heal properly [close window] pathognomonic: distinctively characteristic of a paritcular disease or condition [close window] peripheral blood: this is blood drawn from a superficial vein rather than from a venous catheter such as a Broviac [close window] phenotype: Manifestation of a genotype, or genetic instruction, or the combined manifestation of several different genotypes. Phenotype is the immediate cause of genetic disease and object of genetic selection. [close window] placenta: a vascularized organ in mammals that unites fetus to the mother's uterus, providing nourishment to and ridding the fetus of waste without direct contact between maternal and fetal blood. [close window] postnatal: after birth [close window] precipitate: to cause a substance in solution to separate as a solid [close window] pulmonary edema: abnormal accumulation of fluid in the lungs [close window] pulmonary embolism: obstruction of an artery or one of its branches in the lungs by a blood clot [close window] pulmonary fibrosis: lung scarring; formation of fibrous tissue in the lung as a reparative or reactive process, as opposed to formation of fibrous tissue as a normal constituent of and organ or tissue [close window] red cell: also erythrocyte, a red cell is the component of blood that contains hemoglobin, which transports oxygen from the lungs to the body's tissues; normal life span is about 120 days [close window] renal: relating to, involving, affecting, or located in the region of the kidneys [close window] reticulocyte: a young red cell (erythrocyte) released by the bone marrow that contains no nucleus but has residual RNA; normally composes about 1% of circulating blood cells. The reticulocyte count is increased in hemolytic anemia. [close window] septicemia: systemic disease caused by the multiplication of microorganisms in the ciculating blood; formerly called "blood poisoning" [close window] Southeast Asia: region of Asia bound by India in the West, China in the North, and the Pacific Ocean in the East; includes Brunei, Burma, Cambodia, Laos, Malaysia, the Philippines, Singapore, Thailand and Vietnam [close window] spleen: an organ in the upper left quadrant of the abdomen that is important in immune function and in the maintenance of normal red blood cell anatomy. The spleen is the largest single immune organ in the body, playing a particularly important role in clearing some bacteria from the blood duing infection. The spleen contains immune cells that activate the immune system (T cells) and produce antibodies (B cells). Red blood cells that are old or not normal in any other way are disintegrated by the spleen, releasing hemoglobin. This hemoglobin is converted to bilirubin by the liver and leads to jaundice. If the spleen is required to remove more than the usual red blood cells, it can become enlarged and increase its function, leading to increased hemolysis and jaundice. [close window] splenectomy: surgical removal of the spleen resulting in loss of immune function. Used judicially, this procedure can increase hemoglobin in some patients who have a hemolytic anemia and decrease transfusion requirements in chronically-transfused patients. This procedure can lead to splenic and hepatic vein thrombosis in individuals who have Hemoglobin H-Constant Spring; prophylatic anticoagulation should be considered immediately after surgery with continued prophylaxis for life. [close window] splenomegaly: enlargement of the spleen due to its increased activity in filtering red blood cells or other disease process [close window] soluble: capable of being dissolved [close window] stem cells: precursors to red blood cells and all types of white cells [close window] tachycardia: rapid beating of the heart, conventionally applied to rates over 100 beats per minute during physical examination [close window] target cells: red blood cells with a reduced amount of hemoglobin, weakening the cell structure and causing membrane walls to collapse and stick to each other in the center, producing a target-like appearance; commonly associated with hypochromic, microcytic anemic conditions such as thalassemia [close window] thrombocytopenia: a condition in which there is an abnormally low number of platelets (blood clotting particles) in the circulating blood; this can be an occurrence during splenomegaly (abnormal enlargement of the spleen) [close window] thrombocytosis: abnormal increase in the number of platelets (blood clotting particles) ciculating in the blood. This is a common occurrence after splenectomy. [close window] thrombosis: the formation or presence of a blood clot within a blood vessel [close window] toxemia: an abnormal condition associated with the presence of toxic substances in the blood, generally used in conjunction with 'toxemia of pregnancy,' an occurrence near the end of pregnancy that can cause maternal hypertension and other complications [close window] Transcaucasia: region of Georgia, Armenia, and Azerbaijan between the Caucasus Mountains and the borders of Turkey and Iran [close window] transcription: the process of constructing a messenger RNA molecule using a DNA molecule as a template with resulting transfer of genetic information to the messenger RNA [close window] translation: the process of forming a protein molecule at a ribosomal site of protein synthesis from information contained in messenger RNA [close window] ultrasound: a non-invasive imaging method involving the use of sound waves which will form a two-dimensional image when bounced off of structures (e.g. organs, a fetus) inside the body. [close window] urticaria: an allergic disorder marked by raised patches of skin or mucous membrane and intense itching, and caused by contact with a specific precipitating factor either externally or internally (as by food, drug, inhalant or transfusion) [close window]