| ABSCESS: Inflamed tissue, including an area of pus. |
| ABSOLUTE CD4 CELL COUNT (T4 COUNT): See CD4 Cell Count. |
| ACCELERATED APPROVAL: Expedited process for FDA approval of treatments for serious or life-threatening conditions. |
| ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS): The most severe manifestation of infection with HIV. The CDC lists numerous opportunistic infections and neoplasms (cancers) that, in the presence of HIV infection, constitute an AIDS diagnosis. In 1993, the CDC expanded the criteria for an AIDS diagnosis to include CD4 cell count at or below 200 cells/mm³ in the presence of HIV infection. In persons (age 5 and older) with normally functioning immune systems, CD4 cell counts usually range from 800 to 1,500 cells/mm³. Persons living with AIDS often have infections of the lungs, brain, eyes, and other organs, debilitating weight loss, diarrhea, and malignancies. |
| ACTG: See AIDS Clinical Trials Group. |
| ACTIVE IMMUNITY: Immunity produced by the body in response to stimulation by a disease-causing organism or other antigen, such as a vaccine. |
| ACUPUNCTURE: A Chinese medical treatment involving the insertion of very fine sterile needles into the body at specific points according to a mapping of "energy pathways." Historically, acupuncture is one component of an overall program of Chinese medicine that includes theory, practice, diagnosis, physiology, and the use of herbal preparations. Acupuncture is used to control pain and to treat other conditions such as allergies or addiction withdrawal. See Alternative Medicine. |
| ACUTE HIV INFECTION: The four- to seven-week period of rapid viral replication following exposure to HIV. During acute infection, high levels of plasma HIV RNA (viral load) disseminate throughout the body, accompanied by a sharp drop in CD4 cell count. An estimated 30% to 60% of individuals with acute HIV infection develop a syndrome characterized by fever, malaise, lymphadenopathy, pharyngitis, headache, myalgia, and, sometimes, rash. Usually within 30 to 50 days after acute infection, seroconversion and a broad HIV-1-specific immune response occur. Also called primary HIV infection. |
| ADAP: See AIDS Drug Assistance Programs. |
| ADENOPATHY: Any disease involving or causing enlargement of glandular tissues, especially one involving the lymph nodes. |
| ADENOSINE: A nucleoside combining the base adenine with D-ribose. One of the building blocks of DNA and RNA. |
| ADENOVIRUS: Any virus from the family Adenoviridae. More than 40 adenoviruses are known to infect people, causing upper respiratory tract, gastrointestinal, and eye infections. |
| ADHERENCE: Taking medications or undergoing other treatment as prescribed, including frequency and food restrictions. Nearly-perfect adherence to anti-HIV regimens is typically required to avoid the development of drug resistance. Also called compliance. |
| ADJUVANT: A substance added to a drug formulation that facilitates or modifies the action of the principal ingredient. May be used in HIV therapies or for HIV vaccines. Examples of adjuvants include Freund incomplete adjuvant and Montanide incomplete seppic adjuvant. |
| ADMINISTRATION (ROUTE OF ADMINISTRATION): How a drug or therapy is introduced into the body. Systemic administration means that the drug goes throughout the body (usually carried in the bloodstream), and includes oral (by mouth), intravenous (injection into a vein, IV), intramuscular (injections and neoplasms (cancers) that, in the presence of HIV infection, constitute an AIDS diagnosis. In 1993, the CDC expanded the criteria for an AIDS diagnosis to include CD4 cell count at or below 200 cells/mm³ in the presence of HIV infection. In persons (age 5 and older) with normally functioning immune systems, CD4 cell counts usually range from 800 to 1,500 cells/ mm³. Persons living with AIDS often have infections of the lungs, brain, eyes, and other organs, debilitating weight loss, diarrhea, and maligtion into a muscle, IM), intrathecal (into the spinal canal), subcutaneous (beneath the skin, sc), and rectal administration. Local administration means that the drug is applied or introduced into the specific area affected by the disease, such as application directly onto the affected skin surface (topical administration). The effects of most therapies depend upon the ability of the drug to reach the affected area; thus the route of administration and consequent distribution of a drug in the body are important determinants of its effectiveness. |
| ADVERSE EVENT: An unwanted effect, especially as defined in clinical trials. Specifically, drug-related adverse events are those that are considered by the investigators to be caused by the study drug. Also called adverse reactions. |
| AEROSOLIZED: A form of drug administration in which the agent is turned into a fine spray or mist and inhaled. |
| AETC: See AIDS Education and Training Centers. |
| AFEBRILE: Without fever; having a normal body temperature. |
| AGAMMAGLOBULINEMIA: Absence or low levels of the gamma fraction of serum globulin. Commonly used to describe absence of immunoglobulins in general. See Antibodies. |
| AGENCY FOR HEALTH CARE POLICY AND RESEARCH (AHCPR): An agency of the Department of Health and Human Services supporting activities to enhance health-care services and improve access to them. |
| AHCPR: See Agency for Health Care Policy and Research. |
| AIDS CLINICAL TRIALS GROUP (ACTG): A group of U.S. medical centers that evaluate treatment for HIV and HIV-associated infections. ACTG studies-both adult and pediatric-are sponsored by the National Institute of Allergy and Infectious Diseases and the National Institute of Child Health and Human Development (for many of the pediatric studies) of the National Institutes of Health. |
| AIDS DRUG ASSISTANCE PROGRAMS (ADAP): State-based programs funded in part by Title II of the Ryan White CARE Act that provide therapeutics (including devices necessary to administer pharmaceuticals) to treat HIV disease or prevent the serious deterioration of health, including treatment of opportunistic infections. ADAP formularies and eligibility criteria are determined state by state with a focus on serving low-income individuals. |
| AIDS EDUCATION AND TRAINING CENTERS (AETC): The Health Resources and Services Administration (HRSA) supports a network of 15 regional centers that serve as resources for educating health professionals in prevention, diagnosis, and care of HIV-positive patients. The centers train primary caregivers to incorporate HIV prevention strategies into their clinical priorities, along with diagnosis, counseling, and care of HIV-positive persons and their families. |
| AIDS RESEARCH ADVISORY COMMITTEE (ARAC): A board that advises and makes recommendations to the Director, National Institute of Allergy and Infectious Diseases, on all aspects of HIV-related research, vaccine development, pathogenesis, and epidemiology. |
| AIDS WASTING SYNDROME: Involves involuntary loss of 10% of baseline body weight plus either chronic diarrhea (two loose stools per day for more than 30 days) or chronic weakness and documented fever (for 30 days or more, intermittent or constant) in the absence of a concurrent illness or condition other than HIV infection that would explain the findings. |
| AIDS-DEFINING ILLNESS: Any one of a number of serious diseases that, if experienced by a person with HIV, is sufficient for a diagnosis of AIDS. According to the CDC, some AIDS-defining illnesses are PCP, MAC, AIDS wasting syndrome, KS, and invasive cervical cancer. A CD4 cell count <200 cells/mm³ is an AIDS-defining condition. |
| AIDS-RELATED CANCERS: Several cancers are more common or more aggressive in persons living with HIV. These malignancies include lymphomas, KS, and anogenital cancers that primarily affect the anus and the cervix. HIV, or the immune suppression it induces, appears to play a role in the development of these cancers. |
| AIDS: See Acquired Immunodeficiency Syndrome. |
| AIRBORNE TRANSMISSION: Process by which an infectious agent passes through the air to infect susceptible individuals by droplet infection (eg, sneezing, coughing). |
| ALANINE AMINOTRANSAMINASE (ALT): A liver enzyme that plays a role in protein metabolism. Elevated serum levels of ALT are a sign of liver damage from disease or drugs. Also called serum glutamic-pyruvic transaminase (SGPT). |
| ALBUMIN: A protein component of blood serum. |
| ALKALINE PHOSPHATASE: An enzyme normally present in certain cells within the liver, bone, kidneys, intestine, and placenta. When the cells are destroyed in those tissues, more of the enzyme leaks into the blood, and levels rise in proportion to the severity of the condition. Measurement of this enzyme is used as an indication of the health of the liver. |
| ALLERGY: An immediate or delayed immune reaction caused by exposure to an antigen (allergen). |
| ALOPECIA: Partial or complete hair loss. Certain chemotherapeutic cancer drugs cause hair loss because these agents target rapidly dividing cells, including hair cells. |
| ALTERNATIVE MEDICINE: A broad category of treatment systems (eg, chiropractic, herbal medicine, acupuncture, homeopathy, naturopathy, and spiritual devotions) or culturally based healing traditions such as Chinese, Ayurvedic, and Christian Science. Alternative medicine is also referred to as complementary medicine. Holistic medicine is a narrower term. |
| ALUM: Potassium aluminum sulfate, or ammonium aluminum sulfate, used especially as an emetic (an agent that induces vomiting), an astringent (a substance that contracts tissues), and a styptic (a substance that tends to check bleeding by contracting the tissues or blood vessels). |
| ALVEOLUS: A small cavity or socket. Pulmonary alveoli are thin-walled saclike ends of bronchioles where gas exchange takes place. |
| AMEBIASIS: An inflammation of the intestines caused by infestation with Entameba histolytica (a type of ameba) and characterized by frequent loose stools flecked with blood and mucus. |
| AMINO ACID: Any of a class of nitrogen-containing acids. Some 20 amino acids are commonly found in animals and humans. Chains of amino acids synthesized by living systems are called polypeptides (up to about 50 amino acids) and proteins (more than 50 amino acids). See Peptide; Proteins. |
| AMYLASE: An enzyme secreted by the salivary glands and the pancreas that helps in the digestion of carbohydrates. Elevated levels may be a sign of pancreatitis. |
| ANABOLIC: Pertaining to anabolism, the metabolic process of building tissue from simpler molecules. |
| ANALOG: In chemistry, a compound with a structure similar to that of another compound but differing from it in respect to certain components or structural makeup, which may have a similar or opposite action metabolically. |
| ANAMNESTIC RESPONSE: The heightened immunologic reaction elicited by a second or subsequent exposure to particular antigen such as a pathogenic microorganism (eg, bacterium, fungus). |
| ANAPHYLACTIC SHOCK: A life-threatening allergic reaction characterized by a swelling of body tissues (including the throat) and a sudden decline in blood pressure. |
| ANDROGEN: A natural or synthetic hormone, such as androsterone or testosterone, with masculizing effects. |
| ANEMIA: A lower than normal number of red blood cells. |
| ANERGY: 1. The loss or weakening of the body's immunity to an irritating agent, or antigen. Anergy can be thought of as the opposite of allergy, which is an overreaction to a substance. The strength of the body's immune response is often quantitatively measured by means of a skin test in which a solution containing an antigen known to cause a response, such as mumps or candida, is injected immediately under the skin. Patients may be so immunologically suppressed that they are unable to produce cutaneous (skin) delayedtype hypersensitivity reaction (DTH). Such patients usually do not test positive for tuberculosis on a tuberculin skin test (or Mantoux test). The lack of a reaction to these common antigens indicates anergy. 2. Researchers have found that CD4 cells in cell culture can be turned off by contact with the HIV envelope, leaving them unable to respond to further immune system stimulation. |
| ANGINA: A severe, often constricting pain, usually referring to chest pain. |
| ANGIOGENESIS: The process of forming new blood vessels. Angiogenesis is essential for tumor growth. |
| ANOREXIA: Lack or loss of appetite that causes significant weight loss. |
| ANOSCOPY: A visual examination of the anal canal with an anoscope. |
| ANTAGONISM: Opposing action between agents (eg, drugs), or when the combined effect is less than the effect of one of the agents alone. |
| ANTENATAL: See Prenatal. |
| ANTI-IDIOTYPE: An antibody that recognizes and binds to another antibody (idiotype). |
| ANTIARRHYTHMIC: A drug or procedure that counters or prevents cardiac arrhythmia. |
| ANTIBIOTIC: A substance derived from mold or bacteria that inhibits the growth of other microorganisms (such as bacteria or fungi). Antibiotics are used to treat infectious diseases. |
| ANTIBODIES: Molecules in the blood or secretory fluids that tag, destroy, or neutralize bacteria, viruses, or other harmful toxins (see Antigens). They are members of a class of proteins known as immunoglobulins, which are produced and secreted by B lymphocytes in response to stimulation by antigens. An antibody is specific to an antigen. |
| ANTIBODY-DEPENDENT CELL-MEDIATED CYTOTOXICITY (ADCC): An immune response in which antibodies bind to target cells, identifying them for attack by the immune system. |
| ANTIEMETIC: A drug used to treat nausea or vomiting. |
| ANTIFOLATE: An agent that inhibits intracellular production of folinic acid. |
| ANTIGEN: Any substance that antagonizes or stimulates the immune system to produce antibodies (ie, proteins that fight antigens). Antigens are often foreign substances such as bacteria or viruses. |
| ANTINEOPLASTIC: Inhibiting or preventing the growth of tumor cells. |
| ANTIRETROVIRAL AGENTS: Substances used against retroviruses such as HIV. |
| ANTISENSE DRUG: A synthetic length of DNA, RNA, or molecules with similar structure containing a nucleotide base sequence complementary to the genetic sequence that it is supposed to inactivate. Antisense drugs are designed to lock into and block viral genetic instructions, marking them for destruction by cellular enzymes. This prevents the building of new virus or the infection of new cells. |
| ANTITOXINS: Antibodies that recognize and inactivate toxins produced by certain bacteria, plants, or animals. |
| ANTIVIRAL: A substance or process that destroys or weakens a virus or interferes with its ability to replicate. |
| APHASIA: Loss of ability to speak or understand speech. |
| APHTHOUS ULCER: A painful oral or esophageal sore on a mucous membrane. The size of an ulcer can range from several millimeters to 2 cm in diameter and can occur as single or multiple lesions. Also called canker sores, recurrent ulcerative stomatitis, or ulcerative stomatitis. |
| APOPTOSIS: Cellular suicide or programmed cell death. HIV may induce apoptosis in both infected and uninfected immune system cells. Normally when CD4 cells mature in the thymus gland, a small proportion of these cells are unable to distinguish self from nonself. Because these cells would otherwise attack the body's own tissues, they receive a biochemical signal from other cells that results in apoptosis. See Tumor Necrosis Factor. |
| AREA UNDER THE CURVE (AUC): In pharmacokinetics, a mathematical calculation to evaluate the body's total exposure over time to a given drug. In a graph plotting how drug concentration in the blood changes after dosing, the drug concentration variable lies on the y-axis and time lies on the x-axis. The area between a drug concentration curve and the x-axis for a designated time interval is the AUC. AUCs are used as a guide for dosing schedules and to compare the different drugs' availability in the body. |
| ARM: One group of participants in a comparative clinical trial, all of whom receive the same treatment. The other arm(s) receive(s) a different treatment. |
| ARRHYTHMIA: A change in the heartbeat's rhythm. |
| ARTHRALGIA: Pain in a joint, not inflammatory in character. |
| ASPARTATE AMINOTRANSAMINASE (AST): A liver enzyme that plays a role in protein metabolism. Elevated serum levels of AST are a sign of liver damage from disease or drugs. Also called SGOT (Serum Glutamic-Oxaloacetic Transaminase). |
| ASSAY: A test to detect the presence, absence, or quantity of an agent (such as a drug or viral load). |
| ASSEMBLY AND BUDDING: Final stages of the viral life cycle. Viral core proteins, enzymes, and RNA (see Ribonucleic Acid) gather just inside the cell's membrane, while the viral envelope proteins aggregate within the membrane. An immature viral particle is formed and then pinches off from the cell, acquiring an envelope and the cellular and HIV proteins from the cell membrane. The immature viral particle then undergoes processing by an HIV enzyme called protease to become an infectious virus. |
| ASTHENIA: Weakness. |
| ASYMPTOMATIC: Without symptoms. In HIV/AIDS literature, this term is often used to describe someone who has a positive reaction to one of several tests for HIV antibodies but who shows no clinical symptoms of the disease. |
| ATAXIA: Lack of voluntary muscle coordination. |
| ATTENUATED: Weakened or decreased. |
| AUTOANTIBODY: 1. An antibody that is active against some of the tissues of the organism that produced it. 2. An antibody directed against the body's own tissue. |
| AUTOIMMUNE DISEASE: A condition that results when the immune system responds against a person's own tissues or cells. |
| AUTOIMMUNIZATION: Inducing immunity against the body's own tissues. |
| AUTOINOCULATION: A secondary infection originating from a focus of infection already in the body. |
| AUTOLOGOUS: Pertaining to the same organism or one of its parts; originating within an organism itself (eg, reserving your blood for your future surgery is an autologous transfusion). |
| AZOTEMIA: Abnormally high concentrations of urea and other nitrogenous substances in the blood. |