Hepatitis C Glossary of Terms

Abdominal: Relating to the abdomen, the belly , that part of the body that contains all of the structures between the chest and the pelvis . The abdomen is separated anatomically from the chest by the diaphragm , the powerful muscle spanning the body cavity below the lungs .
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Abdominal cavity: The cavity within the abdomen, the space between the abdominal wall and the spine.
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Abnormal: Not normal. Deviating from the usual structure, position, condition, or behavior. In referring to a growth, abnormal may mean that it is cancerous or premalignant (likely to become cancer ).
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Acquired: Anything that is not present at birth but develops some time later. In medicine, the word "acquired" implies "new" or "added." An acquired condition is "new" in the sense that it is not genetic (inherited) and "added" in the sense that was not present at birth.
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Acute: Of abrupt onset, in reference to a disease. Acute often also connotes an illness that is of short duration, rapidly progressive, and in need of urgent care.
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Alanine: An amino acid, one of the 20 building blocks of protein. Alanine is not an "essential" amino acid. It is not essential to the diet, but can be made by the body from other substances. Alanine was discovered in protein in 1875. Symbol: Ala.

Albumin: The main protein in human blood and the key to the regulation of the osmotic pressure of blood. Chemically, albumin is soluble in water, precipitated by acid, and coagulated by heat.
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Allergy : A misguided reaction to foreign substances by the immune system , the body system of defense against foreign invaders, particularly pathogens (the agents of infection ). The allergic reaction is misguided in that these foreign substances are usually harmless. The substances that trigger allergy are called allergen. Examples include pollens , dust mite, molds , danders , and certain foods. People prone to allergies are said to be allergic or atopic .
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Aminotransferase: An enzyme that catalyzes the transfer of an amino group from a donor molecule to a recipient molecule. The donor molecule is usually an amino acid while the recipient (acceptor) molecule is usually an alpha-2 keto acid. An aminotransferase is also called a transaminase. Two of the better known enzymes in this class are serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT). Both of these transaminases (SGOT and SGPT) are normally found primarily in cells in the liver and heart, are released into the bloodstream as the result of liver or heart damage, and so are used as liver and heart tests.

Anemia: The condition of having less than the normal number of red blood cells or less than the normal quantity of hemoglobin in the blood. The oxygen-carrying capacity of the blood is, therefore, decreased.
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Antibody: An immunoglobulin, a specialized immune protein , produced because of the introduction of an antigen into the body, and which possesses the remarkable ability to combine with the very antigen that triggered its production.
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Antiviral: An agent that kills a virus or that suppresses its ability to replicate and, hence, inhibits its capability to multiply and reproduce.
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Antiviral agent: An agent that kills viruses or suppresses their replication and, hence, inhibits their capability to multiply and reproduce.
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Arthritis: Inflammation of a joint. When joints are inflamed they can develop stiffness, warmth, swelling, redness and pain. There are over 100 types of arthritis. (see osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis, lupus, gout, pseudogout).

Ascites: Abnormal buildup of fluid in the abdomen. Ascites can occur as a result of a number of conditions, including severe liver disease and the presence of malignant cells within the abdomen.

Assay: An assay is an analysis done to determine:

1. The presence of a substance and the amount of that substance. Thus, an assay may be done for example to determine the level of thyroid hormones in the blood of a person suspected of being hypothyroid (or hyperthyroid).
2. The biological or pharmacological potency of a drug. For example, an assay may be done of a vaccine to determine its potency.

Bilirubin: A yellow-orange compound produced by the breakdown of hemoglobin from red blood cells.
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Biochemical: Relating to biochemistry, the application of the tools and concepts of chemistry to living systems.
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Biopsy: The removal of a sample of tissue for purposes of diagnosis. (Many definitions of "biopsy" stipulate that the sample of tissue is removed for examination under a microscope. This may or may not be the case. The diagnosis may be achieved by other means such as by analysis of chromosomes or genes.)
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Blood pressure: The blood pressure is the pressure of the blood within the arteries. It is produced primarily by the contraction of the heart muscle. It's measurement is recorded by two numbers. The first (systolic pressure) is measured after the heart contracts and is highest. The second (diastolic pressure) is measured before the heart contracts and lowest. A blood pressure cuff is used to measure the pressure. Elevation of blood pressure is called "hypertension".

Blood transfusion : The transfer of blood or blood components from one person (the donor) into the bloodstream of another person (the recipient). This may be done as a lifesaving maneuver to replace blood cells or blood products lost through bleeding. Transfusion of your own blood (autologous) is the safest method but requires advance planning and not all patients are eligible. Directed donor blood allows the patient to receive blood from known donors. Volunteer donor blood is usually most readily available and, when properly tested has a low incidence of adverse events. Blood conserving techniques are an important aspect of limiting transfusion requirements.
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Bone marrow: The soft blood-forming tissue that fills the cavities of bones and contains fat and immature and mature blood cells, including white blood cells, red blood cells, and platelets. Diseases or drugs that affect the bone marrow can affect the total counts of these cells.

Cancer: An abnormal growth of cells which tend to proliferate in an uncontrolled way and, in some cases, to metastasize (spread).
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Carcinoma: Cancer that begins in the skin or in tissues that line or cover body organs. For example, carcinoma can arise in the breast , colon, liver, lung, prostate, and stomach.
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CDC: The Centers for Disease Control and Prevention , the US agency charged with tracking and investigating public health trends. The stated mission of the CDC is "To promote health and quality of life by preventing and controlling disease, injury, and disability." The CDC is a part of the U.S. Public Health Services (PHS) under the Department of Health and Human Services (HHS).
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Cell: The basic structural and functional unit in people and all living things. Each cell is a small container of chemicals and water wrapped in a membrane .
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Chronic: This important term in medicine comes from the Greek chronos, time and means lasting a long time.
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Cirrhosis: An abnormal liver condition characterized by irreversible scarring of the liver. Alcohol and viral hepatitis B and C are among the many causes of cirrhosis. Cirrhosis can cause yellowing of the skin (jaundice), itching, and fatigue. Diagnosis of cirrhosis can be suggested by physical examination and blood tests, and can be confirmed by liver biopsy in some patients. Complications of cirrhosis include mental confusion, coma, fluid accumulation (ascites), internal bleeding, and kidney failure. Treatment of cirrhosis is designed to limit any further damage to the liver as well as complications. Liver transplantation is becoming an important option for patients with advanced cirrhosis.

Coma: A state of deep unarousable unconsciousness.
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Cough: A rapid expulsion of air from the lungs typically in order to clear the lung airways of fluids, mucus, or material. Also called tussis.

Cryoglobulinemia: The presence in blood of abnormal proteins called cryoglobulins that, by definition, have the unusual properties of precipitating from the blood serum when it is chilled and redissolving upon rewarming. (Cryoglobulins are gamma globulins with a molecular weight of approximately 200,000.)
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Dengue: Also known as Dengue fever, an acute mosquito-borne viral illness of sudden onset that usually follows a benign course with headache, fever, prostration, severe joint and muscle pain, swollen glands (lymphadenopathy) and rash. The presence (the "dengue triad") of fever, rash, and headache (and other pains) is particularly characteristic of dengue. Dengue is endemic throughout the tropics and subtropics. It goes by other names including breakbone or dandy fever. Victims of dengue often have contortions due to the intense joint and muscle pain. Hence, the name "breakbone fever." Slaves in the West Indies who contracted dengue were said to have "dandy fever" because of their postures and gait.

Depression : An illness that involves the body, mood, and thoughts, that affects the way a person eats and sleeps, the way one feels about oneself, and the way one thinks about things. A depressive disorder is not the same as a passing blue mood. It is not a sign of personal weakness or a condition that can be wished away. People with a depressive disease cannot merely "pull themselves together" and get better. Without treatment, symptoms can last for weeks, months, or years. Appropriate treatment, however, can help most people with depression.
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Diabetes: Refers to diabetes mellitus or, less often, to diabetes insipidus . Diabetes mellitus and diabetes insipidus share the name "diabetes" because they are both conditions characterized by excessive urination (polyuria).
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Diagnosis: 1 The nature of a disease ; the identification of an illness. 2 A conclusion or decision reached by diagnosis. The diagnosis is rabies . 3 The identification of any problem. The diagnosis was a plugged IV.
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DNA: Deoxyribonucleic acid. One of two types of molecules that encode genetic information. (The other is RNA . In humans DNA is the genetic material; RNA is transcribed from it. In some other organisms, RNA is the genetic material and, in reverse fashion, the DNA is transcribed from it.)
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ELISA: ELISA stands for "enzyme-linked immunosorbent assay." This is a rapid immunochemical test that involves an enzyme (a protein that catalyzes a biochemical reaction). It also involves an antibody or antigen (immunologic molecules).
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Encephalopathy: Disease, damage, or malfunction of the brain. In general, encephalopathy is manifested by an altered mental state that is sometimes accompanied by physical changes. Although numerous causes of encephalopathy are known, the majority of cases arise from infection, liver damage, anoxia, or kidney failure. The term encephalopathy is very broad and, in most cases, is preceded by various terms that describe the reason, cause, or special conditions of the patient that leads to brain malfunction. For example, anoxic encephalopathy means brain damage due to lack of oxygen, and hepatic encephalopathy means brain malfunction due to liver disease. Depending upon the cause and severity of the condition, symptoms may range from mild alterations in mental status to severe and potentially fatal manifestations such as dementia, seizures, and coma.

Enzyme: A protein (or protein-based molecule) that speeds up a chemical reaction in a living organism. An enzyme acts as catalyst for specific chemical reactions , converting a specific set of reactants (called substrates) into specific products. Without enzymes, life as we know it would not exist.
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Enzymes: Proteins that act as a catalysts in mediating and speeding a specific chemical reaction .
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Esophageal: Pertaining to the esophagus.

False positive: A result that is erroneously positive when a situation is normal. An example of a false positive: a particular test designed to detect cancer of the toenail is positive but the person does not have toenail cancer.
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Fatigue: A condition characterized by a lessened capacity for work and reduced efficiency of accomplishment, usually accompanied by a feeling of weariness and tiredness. Fatigue can be acute and come on suddenly or chronic and persist.
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Fever : Although a fever technically is any body temperature above the normal of 98.6 degrees F. (37 degrees C.), in practice a person is usually not considered to have a significant fever until the temperature is above 100.4 degrees F (38 degrees C.).
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Flaviviridae: A family of viruses transmitted by mosquitos and ticks that cause some important diseases, including dengue, yellow fever, tick-borne encephalitis virus, and West Nile fever. The flaviviruses are positive-strand RNA viruses containing three structural proteins and a host-derived lipid bilayer.

Genetic: Having to do with genes and genetic information.

Genotype: The genetic constitution (the genome) of a cell, an individual or an organism. The genotype is distinct from its expressed features, or phenotype.
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HCV: Hepatitis C virus.

Heart: The muscle that pumps blood received from veins into arteries throughout the body. It is positioned in the chest behind the sternum (breastbone; in front of the trachea, esophagus, and aorta; and above the diaphragm muscle that separates the chest and abdominal cavities. The normal heart is about the size of a closed fist, and weighs about 10.5 ounces. It is cone-shaped, with the point of the cone pointing down to the left. Two-thirds of the heart lies in the left side of the chest with the balance in the right chest.
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Heart disease: Any disorder that affects the heart. Sometimes the term "heart disease" is used narrowly and incorrectly as a synonym for coronary artery disease. Heart disease is synonymous with cardiac disease but not with cardiovascular disease which is any disease of the heart or blood vessels. Among the many types of heart disease, see, for example: Angina; Arrhythmia; Congenital heart disease; Coronary artery disease (CAD); Dilated cardiomyopathy; Heart attack (myocardial infarction); Heart failure; Hypertrophic cardiomyopathy; Mitral regurgitation; Mitral valve prolapse; and Pulmonary stenosis.

Hemoglobin: The oxygen-carrying pigment and predominant protein in the red blood cells . Hemoglobin forms an unstable, reversible bond with oxygen. In its oxygenated state it is called oxyhemoglobin and is bright red. In the reduced state it is called deoxyhemoglobin and is purple-blue.
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Hemolysis: The destruction of red blood cells which leads to the release of hemoglobin from within the red blood cells into the blood plasma .
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Hepatitis: Inflammation of the liver from any cause.
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Hepatitis A: Inflammation of the liver caused by the hepatitis A virus (HAV). HAV is usually transmitted from person to person by food or drink that has been contaminated with the stool of a person with hepatitis A. This type of transmission is called "fecal-oral." The virus is more easily spread in areas where there are poor sanitary conditions or where good personal hygiene is not observed. In 2003 there were hepatitis A outbreaks in the US associated with eating raw or lightly cooked green onions (scallions). Casual contact, as in a school, office, or another work setting, does not spread the virus.
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Hepatitis B: Inflammation of the liver due to the hepatitis B virus (HBV), once thought to be passed only through blood products. It is now known that hepatitis B can also be transmitted via needle sticks, body piercing and tattooing using un sterilized instruments, the dialysis process, sexual and even less intimate close contact, and childbirth. Symptoms include fatigue, jaundice , nausea, vomiting, dark urine, light stools. Diagnosis is by blood test. Treatment is via anti-viral drugs and/or hepatitis B immunoglobulin (HBIG).
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Hepatitis C: Inflammation of the liver due to the hepatitis C virus (HCV), which is usually spread by blood transfusion, hemodialysis, and needle sticks. HCV causes most transfusion-associated hepatitis, and the damage it does to the liver can lead to cirrhosis and cancer. Transmission of the virus by sexual contact is rare. At least half of HCV patients develop chronic hepatitis C infection. Diagnosis is by blood test. Treatment is via anti-viral drugs. Chronic hepatitis C may be treated with interferon, sometimes in combination with anti-virals. There is no vaccine for hepatitis C. Previously known as non-A, non-B hepatitis.

Hepatitis C virus: A single-stranded RNA virus in the Flaviviridae family that causes hepatitis C. Abbreviated HCV. The HCV genome contains some 10,000 nucleotides and encodes a single polyprotein of 3,000 amino acids. HCV was discovered in 1989. Before that time, hepatitis C was referred to as non-A, non-B hepatitis.

Hepatocellular carcinoma: A tumor in which the cancer starts during adulthood in cells in the liver . Also called adult primary liver cancer.
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Histology: The study of the form of structures seen under the microscope. Also called microscopic anatomy, as opposed to gross anatomy which involves structures that can be observed with the naked eye. Traditionally, both gross anatomy and histology (microscopic anatomy) have been studied in the first year of medical school in the U.S. The word "anatomy" comes from the Greek ana- meaning up or through + tome meaning a cutting. Anatomy was once a "cutting up" because the structure of the body was originally learned through dissecting it, cutting it up. The word "histology" came from the Greek "histo-" meaning tissue + "logos", treatise. Histology was a treatise about the tissues of the body and the cells thereof.

HIV: Acronym for the Human Immunodeficiency Virus , the cause of AIDS (acquired immunodeficiency syndrome). HIV has also been called the human lymphotropic virus type III, the lymphadenopathy-associated virus and the lymphadenopathy virus . No matter what name is applied, it is a retrovirus. (A retrovirus has an RNA genome and a reverse transcriptase enzyme. Using the reverse transcriptase , the virus uses its RNA as a template for making complementary DNA which can integrate into the DNA of the host organism).
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Hypertension: High blood pressure , defined as a repeatedly elevated blood pressure exceeding 140 over 90 mmHg -- a systolic pressure above 140 with a diastolic pressure above 90.
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Immune: Protected against infection. The Latin immunis means free, exempt.

Immune system: A complex system that is responsible for distinguishing us from everything foreign to us, and for protecting us against infections and foreign substances. The immune system works to seek and kill invaders.
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Infection: The growth of a parasitic organism within the body. (A parasitic organism is one that lives on or in another organism and draws its nourishment therefrom.) A person with an infection has another organism (a "germ") growing within him, drawing its nourishment from the person.
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Inflammation: A basic way in which the body reacts to infection , irritation or other injury, the key feature being redness, warmth, swelling and pain . Inflammation is now recognized as a type of nonspecific immune response .
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Injury: Harm or hurt. The term "injury" may be applied in medicine to damage inflicted upon oneself as in a hamstring injury or by an external agent on as in a cold injury. The injury may be accidental or deliberate, as with a needlestick injury. The term "injury" may be synonymous (depending on the context) with a wound or with trauma.

Insomnia: The perception or complaint of inadequate or poor-quality sleep because of one or more of the following: difficulty falling asleep; waking up frequently during the night with difficulty returning to sleep; waking up too early in the morning; or unrefreshing sleep. Insomnia is not defined by the number of hours of sleep a person gets or how long it takes to fall asleep. Individuals vary normally in their need for, and their satisfaction with, sleep. Insomnia may cause problems during the day, such as tiredness, a lack of energy, difficulty concentrating, and irritability.
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Interferon : A naturally occurring substance that interferes with the ability of viruses to reproduce. Interferon also boosts the immune system.
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Itching: An uncomfortable sensation in the skin that feels as if something is crawling on the skin or in the skin, and makes the person want to scratch the affected area.
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Jaundice: Yellow staining of the skin and sclerae (the whites of the eyes) by abnormally high blood levels of the bile pigment bilirubin . The yellowing extends to other tissues and body fluids. Jaundice was once called the "morbus regius" (the regal disease) in the belief that only the touch of a king could cure it.
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Joint: A joint is the area where two bones are attached for the purpose of motion of body parts. A joint is usually formed of fibrous connective tissue and cartilage. An articulation or an arthrosis is the same as a joint.
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Kidney: One of a pair of organs located in the right and left side of the abdomen which clear "poisons" from the blood, regulate acid concentration and maintain water balance in the body by excreting urine. The kidneys are part of the urinary tract. The urine then passes through connecting tubes called "ureters" into the bladder. The bladder stores the urine until it is released during urination.

Lichen planus : A common skin disease with small itchy pink or purple spots on the arms or legs.
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Liver: An organ in the upper abdomen that aids in digestion and removes waste products and worn-out cells from the blood. The liver is the largest solid organ in the body. The liver weighs about three and a half pounds (1.6 kilograms). It measures about 8 inches (20 cm) horizontally (across) and 6.5 inches (17 cm) vertically (down) and is 4.5 inches (12 cm) thick.

Liver biopsy : A procedure in which a small sample of the liver is removed for the diagnosis of abnormal liver conditions.
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Liver disease: Liver disease refers to any disorder of the liver. The liver is a large organ in the upper right abdomen that aids in digestion and removes waste products from the blood.
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Lymph: An almost colorless fluid that travels through vessels called lymphatics in the lymphatic system and carries cells that help fight infection and disease.

Lymphoma: Tumor of the lymphoid tissue. Diagnosis is by biopsy. Treatment may be chemotherapy, radiation, surgery, or medication, depending on the age of the patient and type of tumor.

Marker: A piece of DNA that lies on a chromosome so close to a gene that the marker and the gene are inherited together. A marker is thus an identifiable heritable spot on a chromosome. A marker can be an expressed region of DNA (a gene) or a segment of DNA with no known coding function. All that matters is that the marker can be detected and trailed.
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Marrow: The bone marrow.

Medical history: 1. In clinical medicine, the patient's past and present which may contain clues bearing on their health past, present, and future. The medical history, being an account of all medical events and problems a person has experienced, including psychiatric illness, is especially helpful when a differential diagnosis is needed.
2. The history of medicine.

Microscopic: So small it cannot be seen without the aid of microscope. As opposed to macroscopic (large enough to be seen with naked eye). A tiny tumor is microscopic while a big tumor is macroscopic.
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Mouth: 1. The upper opening of the digestive tract, beginning with the lips and containing the teeth, gums, and tongue. Foodstuffs are broken down mechanically in the mouth by chewing and saliva is added as a lubricant. Saliva contains amylase, an enzyme that digests starch. 2. Any opening or aperture in the body. The mouth in both senses of the word is also called the os, the Latin word for an opening, or mouth. The o in os is pronounced as in hope. The genitive form of os is oris from which comes the word oral.

Muscle: Muscle is the tissue of the body which primarily functions as a source of power. There are three types of muscle in the body. Muscle which is responsible for moving extremities and external areas of the body is called "skeletal muscle." Heart muscle is called "cardiac muscle." Muscle that is in the walls of arteries and bowel is called "smooth muscle."

Nausea: Nausea, is the urge to vomit. It can be brought by many causes including, systemic illnesses, such as influenza, medications, pain, and inner ear disease. When nausea and/or vomiting are persistent, or when they are accompanied by other severe symptoms such as abdominal pain, jaundice, fever, or bleeding, a physician should be consulted.

Necrosis: The death of living cells or tissues. Necrosis can be due, for example, to ischemia (lack of blood flow). From the Greek "nekros" (dead body).

Needlestick injury: A penetrating stab wound from a needle (or other sharp object) that may result in exposure to blood or other body fluids. The main concern is exposure to the blood or other body fluids of another person who may be carrying infectious disease. The pathogens of primary concern are the human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV).
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NIH: The National Institutes of Health. The NIH is an important U.S. health agency. It is devoted to medical research. Administratively under the Department of Health and Human Services (HHS), the NIH consists of 20-some separate Institutes and Centers. NIH's program activities are represented by these Institutes and Centers.
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Pain: An unpleasant sensation that can range from mild, localized discomfort to agony. Pain has both physical and emotional components. The physical part of pain results from nerve stimulation. Pain may be contained to a discrete area, as in an injury, or it can be more diffuse, as in disorders like fibromyalgia . Pain is mediated by specific nerve fibers that carry the pain impulses to the brain where their conscious appreciation may be modified by many factors.
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Platelet: An irregular, disc-shaped element in the blood that assists in blood clotting. During normal blood clotting, the platelets clump together (aggregate). Although platelets are often classed as blood cells, they are actually fragments of large bone marrow cells called megakaryocytes.

Porphyria: A diverse group of diseases in which the production of heme is disrupted. Porphyria is derived from the Greek word "porphyra", which means purple. When heme production is faulty, porphyrins are overproduced and lend a reddish-purple color to urine. All forms of porphyrias are inherited. The key clinical features are skin sensitivity to sunlight and/or by intermittent acute attacks of abdominal and nerve pain.
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Porphyria cutanea tarda: Literally, the late skin form of porphyria , a genetic photosensitive (light-sensitive) skin disease with onset in adult life with substances called uroporphyrins in the urine due to a deficiency of uroporphyrinogen decarboxylase (UROD), an enzyme required for the synthesis of heme (part of hemoglobin , the pigment in red blood cells that carries oxygen ). The hallmarks of porphyria cutanea tarda (PCT) are blisters which become ulcerated in areas of the skin exposed to sunlight, especially on the face, ears and dorsum (back) of the hands. The affected areas of skin also tend to be fragile and show hyperpigmentation (excess pigment) and hypertrichosis (excess hair).
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Pregnancy : The state of carrying a developing embryo or fetus within the female body. This condition can be indicated by positive results on an over-the-counter urine test, and confirmed through a blood test, ultrasound, detection of fetal heartbeat, or an X-ray. Pregnancy lasts for about nine months, measured from the date of the woman's last menstrual period (LMP). It is conventionally divided into three trimesters, each roughly three months long.
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Progressive: Increasing in scope or severity. Advancing. Going forward. In medicine, a disease that is progressive is going from bad to worse.
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Protease: An enzyme that can split a protein into peptides (from which the protein was originally created).
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Proteins: Large molecules composed of one or more chains of amino acids in a specific order determined by the base sequence of nucleotides in the DNA coding for the protein.
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Quality of life: An important consideration in medical care, quality of life refers to the patient's ability to enjoy normal life activities. Some medical treatments can seriously impair quality of life without providing appreciable benefit, while others greatly enhance quality of life.

Rash : Breaking out (eruption) of the skin. Medically, a rash is referred to as an exanthem.
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Raynaud's phenomenon: A condition resulting in discoloration of fingers and/or toes when a person is exposed to changes in temperature (cold or hot) or emotional events.
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Recombinant: A person with a new combination of genes, a combination of genes not present in either parent, due to parental recombination of those genes.
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Recurrence: The return of a sign, symptom or disease after a remission. The reappearance of cancer cells at the same site or in another location is, unfortunately, a familiar form of recurrence.
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Recurrent: Back again. A recurrent fever is a fever that has returned after an intermission: a recrudescent fever.

Red blood cells: The blood cells that carry oxygen. Red cells contain hemoglobin and it is the hemoglobin which permits them to transport oxygen (and carbon dioxide). Hemoglobin, aside from being a transport molecule, is a pigment. It gives the cells their red color (and their name).
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Regimen: With the accent on the first syllable (reg as in Reggie Jackson), a regimen is a plan, a regulated course such as a diet, exercise or treatment, designed to give a good result. A low-salt diet is a regimen.

Rejection: In transplantation biology, the refusal by the body to accept transplanted cells, tissues or organs. For example, a kidney transplanted may be rejected.

Relapse: The return of signs and symptoms of a disease after a patient has enjoyed a remission . For example, after treatment a patient with cancer of the colon went into remission with no sign or symptom of the tumor, remained in remission for 4 years, but then suffered a relapse and had to be treated once again for colon cancer.
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Remission: Disappearance of the signs and symptoms of cancer or other disease. When this happens, the disease is said to be "in remission." A remission can be temporary or permanent.
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Reproduction: The production of offspring. Reproduction need not be sexual. Yeast can reproduce by budding.
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Risk factor: Something that increases a person's chances of developing a disease.

RNA: Short for ribonucleic acid, a nucleic acid molecule similar to DNA but containing ribose rather than deoxyribose. RNA is formed upon a DNA template. There are several classes of RNA molecules.
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RNA virus: A virus in which the genetic material is RNA. The RNA may be either double- or single-stranded.
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Sensitivity: 1. In psychology, the quality of being sensitive. As, for example, sensitivity training, training in small groups to develop a sensitive awareness and understanding of oneself and of ones relationships with others. 2. In disease epidemiology, the ability of a system to detect epidemics and other changes in disease occurrence. 3. In screening for a disease, the proportion of persons with the disease who are correctly identified by a screening test. 4. In the definition of a disease, the proportion of persons with the disease who are correctly identified by defined criteria.

Serum: The clear liquid that can be separated from clotted blood. Serum differs from plasma, the liquid portion of normal unclotted blood containing the red and white cells and platelets. It is the clot that makes the difference between serum and plasma.
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Spleen: An organ located in the upper left part of the abdomen near the stomach . The spleen produces lymphocytes ; it is the largest lymphatic organ in the body. The spleen also filters the blood, serves as a major reservoir for blood and destroys blood cells that are aged.
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Stage: As regards cancer , the extent of a cancer, especially whether the disease has spread from the original site to other parts of the body. See also: Staging .
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Standard of care: 1. A diagnostic and treatment process that a clinician should follow for a certain type of patient, illness, or clinical circumstance. Adjuvant chemotherapy for lung cancer is "a new standard of care, but not necessarily the only standard of care." (New England Journal of Medicine, 2004)
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Subcutaneous: Under the skin. "Subcutaneous" implies just under the skin.
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Swallowing tube: Descriptive term for the esophagus. See: Esophagus.

Tear: A drop of the salty secretion of the lacrimal glands which serves to moisten the conjunctiva and cornea.

Testicles: The testicles (also called testes or gonads) are the male sex glands. They are located behind the penis in a pouch of skin called the scrotum. The testicles produce and store sperm, and they are also the body's main source of male hormones (testosterone). These hormones control the development of the reproductive organs and other male characteristics, such as body and facial hair, low voice, and wide shoulders.

Therapy: The treatment of disease .
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Transfusion: The transfer of blood or blood products from one person (the donor) into another person (the recipient's) bloodstream. In most situations, this is done as a lifesaving maneuver to replace blood cells or blood products lost through severe bleeding. Transfusion of your own blood (autologous) is the safest method but requires planning ahead and not all patients are eligible. Directed donor blood allows the patient to receive blood from known donors. Volunteer donor blood is usually most readily available and, when properly tested has a low incidence of adverse events.
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Ultrasound: High-frequency sound waves. Ultrasound waves can be bounced off of tissues using special devices. The echoes are then converted into a picture called a sonogram. Ultrasound imaging, referred to as ultrasonography, allows physicians and patients to get an inside view of soft tissues and body cavities, without using invasive techniques. Ultrasound is often used to examine a fetus during pregnancy. There is no convincing evidence for any danger from ultrasound during pregnancy.

Vasculitis: Plural: vasculitides. A general term for a group of diseases that feature inflammation of the blood vessels. Each of these diseases is defined by characteristic distributions of blood vessel involvement, patterns of organ involvement, and laboratory test abnormalities. The causes of these vasculitis diseases are usually not known, but immune system abnormality is a common feature.
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Viral: Of or pertaining to a virus. For example, "My daughter has a viral rash ."
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Viremia: The presence of a virus in the blood. Viremia is analogous to bacteremia (the presence of bacteria in the blood) and parasitemia (the presence of a parasite in the blood). Viremia, bacteremia and parasitemia are all forms of sepsis (bloodstream infection).
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Virus: A microorganism smaller than a bacteria, which cannot grow or reproduce apart from a living cell. A virus invades living cells and uses their chemical machinery to keep itself alive and to replicate itself. It may reproduce with fidelity or with errors (mutations)-this ability to mutate is responsible for the ability of some viruses to change slightly in each infected person, making treatment more difficult.
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Viruses: Small living particles that can infect cells and change how the cells function. Infection with a virus can cause a person to develop symptoms. The disease and symptoms that are caused depend on the type of virus and the type of cells that are infected.

Weight loss: Weight loss is a decrease in body weight resulting from either voluntary (diet, exercise) or involuntary (illness) circumstances. Most instances of weight loss arise due to the loss of body fat, but in cases of extreme or severe weight loss, protein and other substances in the body can also be depleted. Examples of involuntary weight loss include the weight loss associated with cancer, malabsorption (such as from chronic diarrheal illnesses ), and chronic inflammation (such as with rheumatoid arthritis).

White blood cell: One of the cells the body makes to help fight infections. There are several types of white blood cells ( leukocytes ). The two most common types are the lymphocytes and neutrophils (also called polymorphonuclear leukocytes, PMNs, or "polys").
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Yellow fever: An acute systemic (bodywide) illness caused by a virus called a Flavivirus . In severe cases, the viral infection causes a high fever, bleeding into the skin, and necrosis (death) of cells in the kidney and liver. The damage done to the liver from the virus results in severe jaundice which yellows the skin. Hence, the "yellow" in "yellow fever."
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Suggested Reading by Our Doctors

• interferon - Describes the medication interferon (Roferon-A, Intron-A, Rebetron, Alferon-N, Peg-Intron, Avonex, Betaseron, Infergen, Actimmune, Pegasys), a drug used in managing many diseases that involve the immune system.
• Liver Blood Tests - Learn about liver blood tests used to detect liver damage disease such as fatty liver, cirrhosis, hepatitis, Tylenol liver damage, and more. This includes measuring the aminotransferases enzymes (AST and ALT levels)
• Diabetes - Learn about type 1 and 2 diabetes (Diabetes Mellitus) symptoms including increased urination, thirst, weight loss, fatigue, nausea, vomiting, skin infections, and blurred vision. Causes and diagnosis information is provided in the information.

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