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Published in the Bulletin of Experimental Treatments for AIDS June 1996 issue, by the San Francisco AIDS Foundation. |
GlossaryCompiled by Liz Highleyman ABSCESS: an isolated accumulation of pus associated with a localized infection. ACCELERATED APPROVAL: FDA regulations governing early marketing approval of promising drugs for life-threatening illnesses. ACUTE: rapid in onset, aggressive. ADENOVIRUS: a family of double-stranded DNA viruses that are the cause of the common cold. AGCUS: atypical glandular cells of undetermined significance. AIDS CLINICAL TRIALS GROUP (ACTG): a NIAID-sponsored group of medical centers, known as AIDS Clinical Trials Units (ACTU), that evaluate treatments for HIV disease and associated illnesses. AIDS-RELATED COMPLEX (ARC): symptomatic HIV infection. An older term used to describe a condition in which a person is HIV positive and has a variety of symptoms that are related to HIV disease (e.g., swollen lymph nodes, night sweats, fever, diarrhea, weight loss) but that do not qualify as AIDS-defining illnesses. ANAPHYLACTIC SHOCK (ANAPHYLAXIS): a life-threatening allergic reaction to a foreign antigen mediated by IgE antibodies. Symptoms include swelling, shortness of breath and a decrease in blood pressure due to capillary dilation. ANDROGEN: a hormone (e.g., testosterone, androsterone) that has masculinizing effects, including stimulation of the male reproductive organs and development of secondary sex characteristics. ANEMIA: an abnormally low number of red blood cells or a decreased concentration of hemoglobin, resulting in a reduction of the supply of oxygen to cells and tissues. ANERGY (adjective ANERGIC): the lack of an immune response to a foreign antigen. ANOREXIA: the lack or loss of appetite for food. ANTIBIOTIC: an agent that inhibits the growth of or destroys microorganisms. ANTIBODY (AB): an immunoglobulin protein secreted by activated plasma cells, which evolve from B-cells, in response to stimulation by an antigen. The antigen/antibody reaction forms the basis of humoral (TH2) immunity. There are 5 types: IgA, IgD, IgE, IgG and IgM. ANTICOAGULANT: an agent that reduces or delays blood coagulation or clotting. ANTIGEN: any agent or substance that stimulates an immune response, e.g., microorganisms or the substances they produce. ANTIGENEMIA: the presence of an antigen in the blood. ANTIHISTAMINE: an agent (e.g., Benadryl) that counteracts the effects of histamine. Antihistamines are used to treat allergic reactions and to block stomach acid production. ANTIOXIDANT: a substance that inhibits the oxidation reaction by binding with and neutralizing free radicals and other highly reactive molecules, thus reducing cellular damage. Some antioxidants are produced by the body, others are available in foods and supplements (e.g., beta carotene, vitamin E, selenium). ANTIRETROVIRAL: an agent used to suppress the activity or replication of retroviruses such as HIV. ANTISENSE: a complementary piece of genetic material (DNA or RNA) that binds to another piece of DNA or RNA and prevents that DNA/RNA from being used to synthesize new proteins. ANTIVIRAL: an agent that interferes with the life cycle of a virus and suppresses its replication. APOPTOSIS: premature programmed cell death. ARM: a group of participants in a research trial who all receive the same treatment (treatment arm) or placebo (control arm). ASCUS: atypical squamous cells of undetermined significance. ASSAY: a test used to detect the presence and/or concentration of a drug, substance or microorganism in the blood and other body fluids or tissues. ASPERGILLOSIS: an uncommon, life-threatening infection caused by the fungus Aspergillus, which typically infects the lungs and sinuses, but can spread through the blood to other organs including the brain, heart or spleen. ASYMPTOMATIC: not feeling or showing outward signs of illness. ATROPHY (adjective ATROPHIC): progressive degeneration, wasting or decrease in size, especially the loss of muscle tissue. ATTENUATE: to weaken or reduce the level of virulence. An attenuated virus has a diminished ability to cause disease. ATYPIA: a condition of being abnormal or not typical. AUTOIMMUNE RESPONSE (AUTOIMMUNITY): a condition in which an individual's immune system fails to recognize its own biochemical markers as being "self" and attacks body tissues as if they were foreign matter. B-CELL (B-LYMPHOCYTE): an immune system cell that carries out the humoral (TH2) immune response. B-cells are produced in the bone marrow and spleen, and mature into plasma cells that produce antibodies. BACTEREMIA: the presence of bacteria in the blood. BASELINE: a known value to which later measurements can be compared, e.g., baseline CD4 cell count. BIAS: a false association that results from the failure to account for some skewing or influencing factor. BILIRUBIN: a yellowish pigment released by red blood cells when they are removed from circulation and broken down. An excess level of serum bilirubin (hyperbilirubinemia) is characterized by jaundice and may indicate stress on the liver. BIOAVAILABILITY: the extent to which a substance (e.g., a drug) is absorbed and circulated in the body. BIOPSY: surgical removal of a small piece of tissue for microscopic examination and/or culture. BLINDING: the process of preventing patients and/or their doctors from knowing whether the patient is taking active drug or placebo; done to reduce bias in drug trials. BLOOD GAS: a gas (e.g., oxygen, carbon dioxide, nitrogen) dissolved in the plasma, or liquid part of the blood. BRANCHED-CHAIN DNA ASSAY (bDNA): an assay for measuring the amount of virus (viral load) in plasma or tissue. BREAKTHROUGH: refers to a condition that has developed despite measures to prevent it, e.g., PCP that occurs while taking a prophlactic drug. BRONCHITIS: an inflammation of the mucous membranes of the bronchial tubes of the lungs. BRONCHOSCOPY: a procedure for inspecting the trachea, bronchial tubes and lungs using a flexible fiber-optic instrument that conducts light. CACHEXIA: a condition of body wasting and general ill-health. CANDIDIASIS: a disease caused by a species of the yeast-like fungus Candida, usually C. albicans. Candidiasis can affect the skin, nails and mucous membranes throughout the body including the mouth, esophagus, vagina, intestines and lungs. CARCINOMA: a malignant tumor of the epithelial cells that line bodily surfaces and cavities. Carcinoma in situ refers to an early stage of cancer that has not invaded surrounding tissues. CARDIOMYOPATHY (MYOCARDIOPATHY): a disease of the myocardium or heart muscle. CD4 CELL (CD4 LYMPHOCYTE, T-HELPER CELL, T4 CELL): a type of white blood cell that carries the CD4 surface marker and helps the body fight infection. CD4 cells engulf and process invaders (e.g., viruses) and release cytokines that coordinate a broad range of immune activity, including killer cell activation and antibody production. CD4 CELL COUNT (T-HELPER CELL COUNT): the number of CD4 lymphocytes present in a cubic millimeter (mm3) of blood. The CD4 count is one indicator of the severity or progression of HIV disease and is sometimes used as a surrogate marker. CD8 CELL (CD8 LYMPHOCYTE, T8 CELL): a type of white blood cell that helps regulate and/or carry out the body's immune response. Two major subsets of T-cells express the CD8 surface marker: T-suppressor cells and cytotoxic T-lymphocytes (CTL). CELL ANTIVIRAL FACTOR (CAF): a factor produced by CD8 cells that has been suggested to block viral infection. The identity of this factor is not known; possibilities include IL-16 and 3 recently identified chemokine proteins, RANTES, MIP-1-alpha and MIP-1-beta. CELL-MEDIATED IMMUNITY (CELLULAR IMMUNITY, TH1 RESPONSE): the immune response mediated by the TH1 subset of CD4 cells. Cell-mediated immunity is stimulated by the cytokines IL-2, IL-12 and gamma interferon and carried out by CD8 cytotoxic T-cells (CTL) and macrophages. CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC): the U.S. federal agency within the Department of Health and Human Services that monitors disease occurrence and develops policies for preventing diseases and maintaining the health of the population. CENTRAL NERVOUS SYSTEM (CNS): the brain and spinal cord. CERVICAL INTRAEPITHELIAL NEOPLASIA (CIN, SQUAMOUS INTRAEPITHELIAL LESION, SIL): abnormal growth of cells of the uterine cervix, suggesting an early stage of cervical cancer. Human papillomavirus (HPV) infection and HIV infection are associated with an increased risk of CIN/SIL. CERVIX (adjective CERVICAL): the cylindrical, lower part of the uterus leading into the vagina. CHRONIC: less intense, slow, persisting over a long period. CLINICAL TRIAL (CLINICAL STUDY): an organized procedure for determining the effectiveness of new drugs or therapies by administering the agent to participants under strictly controlled conditions. CLONE: a group of genetically identical cells or organisms derived from a single common ancestor. CODON: a sequence of 3 nucleotides or bases that encode the information for a particular amino acid (the building blocks that make up proteins). Changes in specific codons can confer resistance to certain drugs. COFACTOR: a substance, microorganism or environmental factor that activates or enhances the action of a disease-causing agent. COHORT: a group of individuals in a study who share a statistical factor. COLONY STIMULATING FACTOR (CSF): a cytokine responsible for controlling the production of white blood cells. Types include granulocyte colony stimulating factor (G-CSF) and granulocyte macrophage colony stimulating factor (GM-CSF). COLPOSCOPY: examination of a tissue surface (particularly the uterine cervix) with a low-powered, lighted microscope (colposcope) to identify abnormal cell growth and, if necessary, remove a tissue sample for biopsy. COMBINATION THERAPY: simultaneous or alternating administration of 2 or more therapies. COMPASSIONATE USE: an FDA classification that allows the use of an experimental drug for a serious illness for which there is no other suitable treatment. CONCOMITANT: occurring together. CONDYLOMATA ACUMINATA: genital and/or anal warts caused by infection with the human papillomavirus (HPV). CONE BIOPSY (CONIZATION): removal of a cone-shaped wedge from the bottom of the uterine cervix to remove lesions and/or to provide a tissue sample for biopsy. CONTRAINDICATION: any circumstance or symptom that makes a method of treatment inadvisable in a particular case. CONTROLLED TRIAL: a clinical trial in which a group receiving an experimental therapy is compared to a control group that is not given the intervention under study. CORTICOSTEROID: one of a group of steroid hormones (e.g., prednisone, cortisone) produced by the outer part of the adrenal gland or manufactured synthetically; corticosteroids have anti-inflammatory and immunosuppressive effects. CROSS-RESISTANCE: the development of resistance to one agent (e.g., drug) which also confers resistance to another (often similar) agent. CRYOTHERAPY (CRYOSURGERY): the use of liquid nitrogen to freeze an abnormal lesion; the lesion typically forms a blister and then heals. CRYPTOCOCCOSIS: an infection caused by a yeast-like fungus, typically Cryptococcus neoformans, found in soil and bird excreta. A common manifestation is cryptococcal meningitis (CM), an inflammation of the membranes surrounding the brain and spinal cord; cryptococcosis may also become disseminated. CRYPTOSPORIDIOSIS: a disease caused by the protozoan Cryptosporidium parvum, which is transmitted to humans by contact with animal feces, contaminated food or water, or oral-anal sexual contact. It can cause severe, chronic diarrhea, gas, weight loss and lymphadenopathy. CURETTE: a sharp, spoon-shaped instrument. Curettage is the process of scraping a cavity with a curette, e.g., to remove abnormal tissue. CYTOCHROME P450 SYSTEM: a process that metabolizes drugs and other foreign substances in the liver, by means of the p450 enzymes. CYTOKINE: an intercellular chemical messenger protein (e.g., interleukin) released by white blood cells. Cytokines facilitate communication among immune system cells and between immune system cells and the rest of the body. CYTOMEGALOVIRUS (CMV, HHV-5): a herpesvirus. CMV infection often occurs in healthy individuals without causing symptoms. In immunocompromised individuals it may cause retinitis, pneumonia, colitis and/or encephalitis. CYTOTOXIC T-LYMPHOCYTE (CTL, T-KILLER CELL): an immune system white blood cell that targets and kills cells infected with microorganisms. CTL action is coordinated by CD4 cells via cytokines. CYTOTOXICITY: the quality of being toxic to or killing cells. DEMENTIA: chronic loss of mental capacity due to organic causes that affects social and/or occupational functioning. DENDRITIC CELL: a type of immune system cell with many branches found in the skin and mucosal linings. DESENSITIZATION: the reduction of sensitivity or allergic reactions to an antigen or drug by administering a very small amount and gradually increasing the dose. DISSEMINATE: to spread; a disseminated infection is one that is distributed throughout the body. DNA (DEOXYRIBONUCLEIC ACID): a molecule found in the nucleus of cells that encodes genetic information. The particular sequence of 4 chemical building blocks (nucleotides) determines an individual's unique genetic code. DOUBLE-BLIND: a type of clinical trial in which neither the subject nor the observer knows what treatment, if any, the subject is receiving. DYSPLASIA: the abnormal development or growth of cells and tissues; precancerous tissue changes. EFFICACY: effectiveness; the ability to achieve a desired effect. EMPIRIC DIAGNOSIS/TREATMENT: evaluation and/or treatment based on observation and experience alone, without relying on laboratory test results or while awaiting lab results. ENCEPHALITIS: inflammation of the brain. ENCEPHALOPATHY: any disease of the brain. ENDOCERVIX: the inner part of the uterine cervix. ENDOCRINE SYSTEM: a system of ductless glands that regulates bodily functions via hormones secreted into the bloodstream. The endocrine glands include the hypothalamus, pituitary gland, thyroid, adrenal glands and gonads (ovaries and testes). ENDOMETRIUM: the mucous membrane that lines the uterus. ENDOSCOPY: a method of examining the interior of a body cavity or hollow organ (e.g., esophagus, stomach) using an endoscope, a narrow flexible fiber optic instrument that conducts light. ENDPOINT: a direct marker of disease progression, e.g., disease symptoms or death. EPITHELIUM: the thin layer of cells that covers the internal and external surfaces of the body, including body cavities, ducts and vessels. EPSTEIN-BARR VIRUS (EBV, HHV-4): a herpesvirus. EBV infection is common in children and may cause infectious mononucleosis in young adults. EBV is associated with oral hairy leukoplakia and some types of cancer. ESOPHAGUS (adjective ESOPHAGEAL): the swallowing tube, the portion of the digestive canal between the oral cavity and the stomach. ESTROGEN: a female sex hormone; a natural or synthetic substance (e.g., estradiol) that stimulates the development of secondary sex characteristics and regulates the reproductive cycle in women. ETIOLOGY: the cause of a diseases; the study of causes of disease. EXOGENOUS: originating or produced outside the body. EXPANDED ACCESS: an FDA program that allows free distribution of experimental drugs through physicians to people with life-threatening illness who have failed or cannot tolerate approved therapies. FIRST-LINE TREATMENT: the preferred standard therapy for a particular condition. FOOD AND DRUG ADMINISTRATION (FDA): the federal agency responsible for regulating the development, use and safety of drugs, medical devices, food, cosmetics and related products. FUNGUS: a class of organisms that includes yeasts, molds and mushrooms, several of which can cause disease (mycoses) in humans, e.g., candidiasis, cryptococcal meningitis and histoplasmosis. FUSIN: a protien necessary for HIV fusion with a host cell. GANGLION: a cluster of nerve tissue primarily composed of neuron cell bodies. GASTROINTESTINAL: relating to the stomach and intestines. GENE (adjective GENETIC): the unit of heredity. A gene contains hereditary information encoded in the form of DNA and is located at a specific position on a chromosome in a cell's nucleus. GENE THERAPY: an approach to preventing and/or treating disease by replacing, removing or introducing genes or otherwise manipulating genetic material, e.g., adding a gene to a cell to produce a specific missing protein. GENOME (adjective GENOMIC): the unique genetic code or hereditary material of an organism. HALF-LIFE: the time required for half the amount of an agent (e.g., drug, virus) to be eliminated from the body. HELPER T-CELL: see CD4 cell. HEPATITIS: an inflammation of the liver that may be caused by several agents, including viruses and toxins. Hepatitis is characterized by jaundice, enlarged liver, fever, fatigue and abnormal liver function tests. Types include hepatitis A (infectious hepatitis), hepatitis B (serum hepatitis) and hepatitis C. HEPATOMEGALY: liver enlargement. HEPATOTOXICITY: poisonous to the liver. HERPES SIMPLEX VIRUS (HSV): a herpesvirus that causes blisters and recurring disease. HSV-1 usually produces lesions on the lips or in the mouth ("cold sores"). HSV-2 is usually sexually transmitted and its lesions generally occur in the anal and/or genital area. Symptomatic disease outbreaks occur at unpredictable intervals of weeks, months or years. HERPESVIRUS: a group of viruses that includes herpes simplex virus types 1 (HSV-1) and 2 (HSV-2), varicella zoster virus (VZV, HHV-3), Epstein-Barr virus (EBV, HHV-4), cytomegalovirus (CMV, HHV-5), human herpesvirus types 6 and 7 (HHV-6, HHV-7) and Kaposi's sarcoma-associated herpesvirus (KSHV or HHV-8). HERPES ZOSTER (SHINGLES): a skin condition characterized by painful blisters that appear in a linear distribution following nerve pathways. Shingles is caused by reactivation of the varicella-zoster virus (VZV) that causes chickenpox; VZV lies dormant in the nerves and reactivates when immune defenses are weakened. HISTOPLASMOSIS: a fungal infection acquired by inhaling spores of the fungus Histoplasma capsulatum which are present in soil or dust. The disease is most often found in the lungs, where it produces a tuberculosis-like inflammation, but it may also disseminate. Symptoms include cough, fever and weight loss. HIVIG: concentrated anti-HIV immunoglobulins used in passive immunotherapy. HIVIG is under study as a treatment for children with HIV disease and as a therapy to prevent vertical transmission. HORMONE: a chemical messenger involved in the regulation and coordination of cellular and bodily functions. HUMAN GROWTH HORMONE (HGH, SOMATOTROPIN, SEROSTIM): a peptide hormone secreted by the anterior pituitary gland. HGH enhances growth by stimulating metabolism and protein synthesis. Recombinant human growth hormone (rHGH) is a genetically engineered drug used for the treatment of HIV-related wasting syndrome. HUMAN LEUKOCYTE ANTIGEN (HLA): a genetic marker of "self" which prevents the immune system from attacking the body's own tissues. HUMAN PAPILLOMAVIRUS (HPV): a papova virus, many strains of which cause warts, including condylomata acuminata (genital warts). Certain strains (e.g., 16, 18) are associated with cervical, anal and oral cancer. HUMORAL IMMUNITY (ANTIBODY-BASED IMMUNITY, TH2 RESPONSE): the immune response mediated by the TH2 subset of CD4 cells. Humoral immunity is stimulated by the cytokines IL-4 and IL-10, and carried out by plasma cells (derived from B-cells) which produce antibodies. HYPERPLASIA: excessive growth of normal cells (i.e., not tumor or cancer cells); an increase in the number of normal cells in a tissue or body part which may increase its size. HYPERTHERMIA: abnormally high body temperature. Also refers to an experimental AIDS therapy in which blood is removed from the body, heated, and returned to the circulation, or in which the patient's whole body is heated. HYPOGAMMAGLOBULINEMIA: low levels of immunoglobulins (antibodies) in the blood. HYSTERECTOMY: surgical removal of the uterus. A radical hysterectomy includes the removal of the upper vagina, fallopian tubes, and possibly the ovaries and lymph nodes. IATROGENIC: refers to an unfavorable response to medical or surgical treatment; symptoms attributable to a medical therapy, e.g., peripheral neuropathy caused by an antiviral drug. IDIOPATHIC: refers to a disease or condition of unknown cause or origin. IMMUNE SYSTEM: the body's defense system that protects against foreign invaders (e.g., microorganisms) and cancerous cells. There are 2 branches: cell-mediated (TH1) and humoral (antibody-based or TH2). Organs of the immune system include the lymph nodes, spleen, thymus, tonsils and bone marrow. IMMUNIZATION: a process by which a person is protected against the adverse effects of infection by a disease-causing microorganism. IMMUNOGEN: an antigenic agent or substance that stimulates an immune response. IMMUNOGLOBULIN (IG): see antibody. IMMUNOMODULATOR (IMMUNE MODULATOR): a substance or process capable of modifying functions of the immune system. Immune modulators include cytokines (e.g., IL-2, gamma interferon) and broad-acting agents (e.g., hormones such as endorphins). IMMUNOSUPPRESSION (IMMUNOCOMPROMISE): reduced function of the immune system; a state in which the immune system defenses have been suppressed or weakened. IMMUNOTHERAPY (IMMUNE BASED THERAPY, IMMUNE MODULATING THERAPY): a therapy that attempts to modify or enhance immune response or reconstitute a damaged immune system, e.g., active immunization (vaccination), cytokine therapy. INDUCTION: the phase of initiation of a particular therapy. INFLAMMATION: the body's response to tissue injury or infection, which typically includes increased vessel dilation and permeability resulting in redness, swelling, heat and pain. INTEGRASE: an enzyme produced by HIV that allows the integration of HIV DNA into the host cell's genetic material. INTENT-TO-TREAT: a method of analysis of medical trials that groups each participant according to the treatment arm to which they were initially assigned (e.g., experimental drug, standard therapy, placebo), regardless of whether they remained in that arm for the duration of the study. INTERFERON: a cytokine (messenger protein) that plays a role in immune response. Interferons are secreted by infected cells and help protect other cells from infection. There are 3 major classes: alpha, beta and gamma. INTERLEUKIN (IL): a cytokine secreted by immune system cells. Various interleukins (e.g., IL-1, IL-2, IL-12) regulate a range of immune system functions. INTOLERANCE: the inability of the body to appropriately metabolize an agent or drug. INTRAVENOUS (IV): introduced directly into a vein. INVESTIGATIONAL NEW DRUG (IND): an FDA classification applied to experimental drugs undergoing trials to assess safety and efficacy prior to marketing approval. IN UTERO: in the uterus; refers to events that occur in the womb before birth. IN VITRO: Latin for "in glass"; refers to work done in a test tube or culture medium in the laboratory. IN VIVO: Latin for "in the body of a living organism"; refers to work done using human (or animal) subjects. IVIG (INTRAVENOUS IMMUNE GLOBULIN): broad-spectrum concentrated immunoglobulins adminstered intravenously to treat conditions in which the body does not produce enough of its own antibodies. KAPOSI'S SARCOMA (KS): an abnormal or cancerous proliferation of cells with increased blood or lymph vessels of the skin, mucous membranes and/or internal organs. KS typically appears as pink or purple flat or raised lesions on the skin or in the mouth. KAPOSI'S SARCOMA-ASSOCIATED HERPESVIRUS (KSHV, HUMAN HERPESVIRUS TYPE 8): a recently discovered herpesvirus that is found in samples of tissue from Kaposi's sarcoma lesions and may be a causal agent or co-factor. KILLER T-CELL: see cytotoxic T-lymphocyte. LESION: any abnormal change in tissue caused by disease or injury. LEUKOCYTE: any immune system white blood cell (e.g., monocyte, CD4 cell). Many types of leukocytes are involved in the body's defense against infection and disease. LEUKOPENIA: an abnormally low number of white blood cells in the circulating blood. LIPOSOME (LIPID VESICLE): a spherical particle of fat suspended in a liquid medium. Liposomes may be used to carry drugs or other substances to cells or tissues. LIVER ENZYME: a protein produced by the liver (e.g., SGOT, SGPT). Abnormally high levels in the blood indicate liver disease or damage (e.g., hepatitis, drug-related liver toxicity). LOG: refers to quantities in factors of 10. A log change is an exponential or 10-fold increase or decrease (e.g., 10 to 100 is a 1 log increase). LONG-TERM NONPROGRESSOR (LTNP): an individual who has been infected with HIV for 7-10 years or more but does not exhibit immune system decline or opportunistic diseases. Long-term survivor refers a person who has lived 7-10 or more years with HIV, but who may or may not have symptomatic disease. LOOP ELECTROSURGICAL EXCISION PROCEDURE (LEEP, LOOP DIATHERMY): utilization of a heated wire loop to remove a cone-shaped wedge from the bottom of the cervix and around the os for biopsy; the loop seals off blood vessels as it cuts. LYMPH NODE: a small, bean-sized organ located throughout the body with concentrations in the neck, groin and armpits. Lymph nodes are the sites of antigen presentation and immune activation. LYMPHADENOPATHY: any abnormality of the lymph nodes. Usually refers to swollen and tender lymph nodes due to, e.g., an infectious disease such as AIDS or mononucleosis. LYMPHATIC SYSTEM (adjective LYMPHOID): a network of vessels, ducts, nodes and organs that help maintain the fluid environment of the body and coordinate immune response. The lymphoid organs include the lymph nodes, spleen, thymus and tonsils. LYMPHOCYTE: a type of white blood cell (e.g., T-cell, B-cell) responsible for immune defenses. LYMPHOMA: a malignant disease (cancer) originating in the lymph nodes. MACROPHAGE: a large scavenger white blood cell that ingests degenerated cells and foreign particles and secretes messenger proteins (monokines) involved in a variety of immune system responses. MAINTENANCE THERAPY (SECONDARY PROPHYLAXIS): preventive therapy that follows successful initial treatment of an illness. MAJOR HISTOCOMPATIBILITY COMPLEX (MHC): cell surface markers (also known as HLA markers) that determine receptor shape and allow immune cells to recognize components of the body (i.e., to distinguish "self" from "non-self"). MHC molecules are necessary for antigen presentation and recognition of antigens by immune system cells. MALIGNANCY (adjective MALIGNANT): cancer; a neoplasm or tumor that grows in an uncontrolled manner, invading nearby tissue or spreading to other sites through the bloodstream. MARKER: lab result or symptom observation used to measure a treatment's effectiveness or an individual's immune system status. Also, a unique identifier on a cell's surface. METABOLISM: the process of building the body's molecular structures from nutrients (anabolism) and breaking them down for energy (catabolism). METASTASIS (adjective METASTATIC, verb METASTASIZE): secondary cancer that has spread via the blood or lymph vessels from the primary or original site to another part of the body. MICROCEPHALY: a birth defect characterized by an abnormally small head, incomplete development of the brain and usually mental retardation. MONOCYTE: a large white blood cell that plays a role in immune defense by acting as a scavenger that destroys invading microorgnisms. Monocytes circulate in the bloodstream; when they migrate to the tissues they mature into macrophages. MONOTHERAPY: use of a single drug or other therapy for treatment. MORBIDITY: sickness. MUCOUS MEMBRANE (MUCOSA): a moist layer of semi-permeable tissue lining the gastrointestinal, respiratory and genitourinary tracts. MUTATION: a change in the character of a gene that is perpetuated in subsequent cell divisions. MYCOBACTERIUM AVIUM COMPLEX (MAC): a disease caused by Mycobacterium avium or Mycobacterium intracellulare, bacilli found in soil and water. In immunosupressed persons, the bacteria can infect lymph nodes, bone marrow, liver, spleen, spinal fluid, lungs and the gastrointestinal tract. Symptoms in-clude diarrhea, wasting, fever, fatigue and spleen enlargement. MYCOPLASMA: a microorganism, of which there are many varieties (e.g., Mycoplasma penetrans), that usually does not cause disease in people with healthy immune systems. Mycoplasma is thought by some to be a cofactor in the development of AIDS. NAIVE: inexperienced. Used to describe an individual who has never taken a certain drug or class of drugs (e.g., AZT-naive, antiretroviral-naive). NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES (NIAID): a component of the National Institutes of Health that conducts federally-funded research aimed at preventing, diagnosing and treating infectious diseases such as AIDS and tuberculosis. NATIONAL INSTITUTES OF HEALTH (NIH): a large biomedical research organization that is part of the U.S. Public Health Service. NIH includes 24 institutes, centers and divisions, several of which perform AIDS-related research. NATURAL KILLER CELL (NK CELL): a type of lymphocyte that attacks and kills cells infected with microorganisms. NECROSIS: localized tissue death. NEF: a gene of HIV that influences viral replication; also the protein produced by that gene. NEOPLASM: a tumor or growth; tissue that develops abnormally or grows more rapidly than normal. A neoplasm may be benign or malignant (cancerous). NEPHROTOXICITY: the property of being poisonous to the kidneys. NEUROPATHY (adjective NEUROPATHIC): any abnormal, degenerative or inflammatory condition of the nerves. See also peripheral neuropathy. NEUTROPENIA: an abnormally low number or a decrease in the number of neutrophils, a type of white blood cell involved in defense against bacteria and fungi. NEW DRUG APPLICATION (NDA): an application made by a drug sponsor to FDA to request marketing approval. NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITOR (NNRTI): a drug (e.g., delavirdine, nevirapine) that inhibits the action of the retroviral reverse transcriptase enzyme, thus blocking viral replication, yet works in a different way than nucleoside analog drugs. NOSOCOMIAL: refers to the acquisition of a new disease or condition within a healthcare setting. NUCLEOSIDE: a precursor to one of the building blocks or bases (adenine, cytosine, guanine, thymine or uracil) that make up genetic material (DNA and RNA). NUCLEOSIDE ANALOG (NA): a synthetic compound (e.g., AZT, ddI, ddC, d4T, 3TC) that mimics one of the building blocks of DNA (nucleotides). These compounds suppress retroviral replication by interfering with the reverse transcriptase enzyme; the synthetic nucleosides cause premature termination of the viral DNA chain. OFF-LABEL: use of an FDA-approved drug for an indication other than that for which the drug was approved. OFFICE OF AIDS RESEARCH (OAR): a federal agency created to coordinate AIDS research done by various federal departments, institutes and agencies. ONCOGEN: an agent (e.g., virus. toxin) that is able to cause neoplastic cell growth, or cancer. ONCOLOGY: the study and treatment of cancer. OPEN LABEL: a drug trial in which both participants and investigators know what drug is being tested and what dose is being used. OPPORTUNISTIC INFECTION (OI): an illness (e.g., PCP, MAC, CMV disease) caused by a microorganism that usually does not cause disease in persons with healthy immune systems, but which may cause serious illness when the immune system is suppressed. ORAL HAIRY LEUKOPLAKIA: a condition thought to be caused by the Epstein-Barr virus characterized by white, raised, usually painless lesions on the sides of the tongue and/or elsewhere in the mouth. OTITIS MEDIA: inflammation of the middle ear. P24: a core protein of HIV produced by the gag gene. Detection of the p24 antigen in the blood or tissues indicates that HIV is actively replicating and may predict disease progression. PANCREATITIS: inflammation of the pancreas, a digestive gland in the abdominal cavity. Symptoms may include intense abdominal pain, nausea, constipation and possibly jaundice. Pancreatitis may be a side effect of some anti-HIV drugs (e.g., ddI). PARENTERAL: given by injection, bypassing the enteral (gastrointestinal) tract. PAROTITIS: inflammation of the parotid gland, the largest of the salivary glands. PATHOGEN (adjective PATHOGENIC): any disease-causing agent, especially a microorganism. PATHOGENESIS: the development of a particular disease, including the specific events involved, bodily tissues or systems affected, mechanisms of damage and timing of the course of disease. PATHOLOGY (adjective PATHOLOGIC): the study of disease, focusing on causes, development and progress, and how the body is affected. PCR: see polymerase chain reaction. PERINATAL: referring to the period around the time of birth. PERINATAL TRANSMISSION: see vertical transmission. PERIPHERAL NEUROPATHY: a disorder of the nerves usually involving the feet and/or hands and sometimes the legs, arms and face. Symptoms may include numbness, tingling or burning, weakness and partial paralysis. It can be a side effect of some anti-HIV drugs (e.g., ddC, ddI). PHARMACOKINETICS: the action of drugs in the body, including the processes of absorption, transformation, distribution to tissues, duration of action and elimination. PHARMACOLOGY: the science of drugs, their sources and how they work; the specialty of preparing and dispensing drugs. PHASE I TRIAL: the first step in human testing of a new drug; these trials evaluate drug safety and toxicity at different dose levels in a small number of volunteers. PHASE II TRIAL: the second step in the evaluation of a new drug in humans; these trials evaluate drug effectiveness and involve more participants than Phase I studies. Phase II studies proceed only if Phase I studies have shown that a drug is acceptably safe. PHASE III TRIAL: the third step in human drug testing; these trials are designed to support and verify information gathered in Phase I and II trials and involve many more volunteers (up to several thousand). Phase III trials may compare the drug being tested to other therapies or to placebo. PLACEBO-CONTROLLED TRIAL: a trial of an experimental therapy in which an inactive substance or mock therapy (placebo) is given to one group while the treatment being tested is given to another, and the results obtained in the different groups are compared. PLACENTA: the vascular organ that connects the fetus and the mother's uterus, through which metabolic exchange between the fetus and mother occurs. Some pathogenic organisms and maternal antibodies may be transfered across the placenta. PLASMA: the fluid, non-cellular portion of circulating blood that carries blood cells and nutrients throughout the body. PNEUMOCYSTIS CARINII PNEUMONIA (PCP): a life-threatening type of pneumonia thought to be caused by a protozoan. PCP is a common opportunistic infection and a leading cause of death in people with AIDS. PNEUMONIA: an inflammatory condition of the lungs in which they become obstructed with fluid, causing difficult breathing and possibly suffocation. Pneumonia may be caused by bacteria, viruses or fungi. POLYMERASE CHAIN REACTION (PCR): a highly sensitive test that uses an amplification technique to detect minute amounts of DNA or RNA in blood or tissue samples. PRENATAL: the period preceding birth, during which the fetus develops in the uterus. PRESUMPTIVE DIAGNOSIS/TREATMENT: treatment based on an assumed diagnosis, prior to receiving confirmatory laboratory test results. PRIMARY INFECTION: the initial introduction of an infectious organism into the body. PRODRUG: a drug that exerts its effects after metabolic changes within the body convert it to a usable or active form. PROGESTERONE: a female steroid hormone with anti-estrogenic effects. Progesterone prepares the uterus for the development of the fertilized ovum and maintains the uterus throughout pregnancy. Synthetic progesterone is used as a contraceptive. PROGNOSIS (adjective PROGNOSTIC): a forecast of the probable course and/or outcome of a disease. PROPHYLAXIS: a treatment that helps to prevent a disease or condition before it occurs (primary prophylaxis) or recurs (secondary prophylaxis). PROTEASE (PROTEINASE): an enzyme that cleaves the large precursor proteins produced from viral RNA into the component parts (e.g., enzymes and structural proteins) that are then assembled into new viral particles; protease is essential for the replication new of infectious viruses. PROTEASE INHIBITOR: a drug (e.g., saquinavir, indinavir, ritonavir) that blocks the action of the protease enzyme that breaks up large proteins produced from viral RNA, thereby preventing HIV replication. PROTEIN: a large molecule consisting of sequences of amino acids. Proteins are major components of living cells and compose hormones, enzymes and immunoglobulins; they are essential for most life functions. PROTOZOAN: an acellular or 1-celled microorganism, some of which can cause disease in humans. PROVIRUS: a viral state in which viral DNA has been inserted into the chromosome of the host cell. PULSE OXIMETRY: a method of measuring the amount of oxygen in the blood by means of a clip-like instrument that attaches to the finger. PURULENT: characterized by the accumulation of pus. PSYCHOPHARMACOLOGY: the use of drugs that affect the psyche or personality. QUANTITATIVE COMPETITIVE POLYMERASE CHAIN REACTION (QC-PCR): a refined, sensitive version of the PCR assay used to detect DNA or RNA (viral load) using competitive RNA samples for comparison. RANDOMIZED TRIAL: an experiment arranged so as to produce a chance distribution of subjects into different treatment groups or arms. RECEPTOR: a specific protein-binding site on a cell's surface or interior. Many drugs exert their effects by binding to receptors and altering normal cellular communication. Viruses enter cells by fusing with receptors on the cell surface and then passing into the interior of the cell. RECOMBINANT: produced by genetic engineering in the laboratory. Recombinant products are designated by a lower-case r (e.g., rHGH). REFRACTORY: resistant to treatment. REMISSION: a lessening of the severity of disease symptoms; a period of time during which symptoms are abated or eliminated. REPLICATION: duplication or reproduction. RESERVOIR: a site where an infectious agent collects and multiplies, e.g., the macrophages and lymph nodes are reservoirs for HIV. RESISTANCE: the ability of a microorganism (e.g., a virus) to lose its sensitivity to a drug. Microorganisms mutate to function and reproduce despite the presence of a drug. RETINITIS: inflammation of the retina, the light-sensitive tissue at the back of the eyeball that transmits visual impulses to the brain. RETROVIRUS: a class of enveloped viruses that have their genetic material in the form of RNA and use reverse transcriptase to translate their RNA into DNA. The retrovirus family includes oncoviruses (e.g., HTLV-1) and lentiviruses (e.g., HIV-1, HIV-2). REVERSE TRANSCRIPTASE (RT): a viral enzyme that allows a retrovirus to translate its genetic material, in the form of RNA, into DNA, which is then integrated into the host cell's chromosomes. REVERSE TRANSCRIPTASE INHIBITOR (RTI): a drug that blocks retroviral replication by interfering with the reverse transcriptase enzyme. RTI include nucleoside analogs (e.g., AZT, ddI) and non-nucleoside reverse transcriptase inhibitors (e.g., nevirapine). RNA (RIBONUCLEIC ACID): a single-stranded nucleic acid made up of nucleotides. RNA is involved in the transcription of genetic information; the information encoded in DNA is translated into messenger RNA (mRNA), which controls the synthesis of new proteins. RNA takes the place of DNA in retroviruses such as HIV. SALVAGE THERAPY: emergency treatment with an experimental drug of a disease or illness that has not responded to standard therapy. SECOND-LINE TREATMENT: the second preferred therapy for a disease or condition. SECONDARY INFECTION: infection with a second or subsequent infectious organism (e.g., bacteria) during the course of an initial infection with another organism (e.g., a virus). SENSITIVITY: the ability of an organism to be affected by a drug or other agent, e.g., a virus is senstive to AZT if AZT is able to prevent viral replication. Also refers to a statistical measure of the accuracy of a screening test, i.e., how likely a test is to label as positive those who have a disease or condition. SEPSIS: the presence of pathogenic (disease-causing) organisms or their toxins in the blood or tissues, and the associated bodily reactions. SEQUELAE: conditions resulting from a disease or injury. SEROCONVERSION: the change in a person's antibody status from negative to positive. SEROPREVALENCE: the rate of HIV-infected individuals in a certain geographic location or population as measured by blood tests. SEROSTATUS (ANTIBODY STATUS): the presence or absence of antibodies in the blood serum. If antibodies are present, a person is said to be seropositive; if no antibodies can be detected, they are said to be seronegative. SERUM: the fluid portion of blood after coagulation; lymphatic fluid. SEXUALLY TRANSMITTED DISEASE (STD, VENEREAL DISEASE): a disease (e.g., syphilis, chlamydia) that is transmitted through sexual contact. SIDE EFFECT: an action or effect of a drug other than that which is intended. The term usually refers to undesired or negative effects such as headache, skin rash or liver damage. SIMIAN IMMUNODEFICIENCY VIRUS (SIV): a viral infection endemic to African green monkeys and similar to HIV-2. SINUSITIS: acute or chronic inflammation or infection of the sinuses (cavities behind the forehead and cheekbones). SPECIFICITY: a statistical measure of the accuracy of a screening test, i.e., how likely a test is to label as negative those who do not have a disease or condition. SPLENOMEGALY: enlargement of the spleen. SPUTUM: mucus or other matter ejected from the bronchi and lungs by coughing or spitting. SQUAMOUS CELL: flat, thin cells that comprise the surface of the skin and the lining of the esophagous, vagina and rectum. SQUAMOUS INTRAEPITHELIAL LESION (SIL): abnormal growth of squamous cells. SIL particularly refers to abnormal cell changes at the squamo-columnar junction of the uterine cervix. Low-grade SIL is considered a precancerous condition. See also cervical intraepithelial neoplasia. STANDARD THERAPY: a therapy that is FDA-approved for a given condition and is widely used as first-line treatment. STATISTICAL SIGNIFICANCE: the probability that an observed outcome of an experiment or trial is due to chance alone. In general, a result is considered to be statistically significant if there is a less than 5% probability that the difference observed would occur by chance alone if the two treatments being compared were equally effective (e.g., a p-value of less than .05). STEM CELL: a precursor cell from which all blood cells are derived. As they mature, stem cells evolve into various types of red and white blood cells. Bone marrow, the site of blood cell production, is rich in stem cells. STENOSIS: the narrowing or tightening of an opening or passage in the body. STEROID: a family of substances that share a similar chemical structure, including many hormones (e.g., testosterone), vitamin D and various drugs. Some steroid drugs are used to lessen inflammatory reactions. STEVENS-JOHNSON SYNDROME: an unusual, severe reaction characterized by blistering and sloughing of the mucous membranes; the visceral organs may also be involved, and the condition can be fatal. The syndrome may result from the use of certain medications such as TMP-SMX. STOMATITIS: inflammation of the mucous membranes of the mouth. STRAIN: a specific genetic variant of a particular organism. SURROGATE MARKER: a marker or sign that can serve in place of a clinical endpoint, e.g., viral load or CD4 cell count. SYNCYTIUM (plural SYNCYTIA): a mass or clump of cells that fuse together to form one "giant cell." In HIV infection syncytium formation can may lead to direct cell-to-cell infection. SYNERGY (SYNERGISM): the action of 2 or more agents (e.g., drugs) working together that produce an effect greater than the combined effect of the same agents used separately. SYSTEMIC: affecting the whole body; not localized. T-CELL (T-LYMPHOCYTE): a type of white blood cell derived from the thymus that participates in a variety of cell-mediated immune responses. There are 3 major types of T-cells: T-helper (CD4), T-suppressor (CD8) and T-killer (cytotoxic T-lymphocytes or CTL). T-HELPER CELL: see CD4 cell. T-KILLER CELL: see cytotoxic T-lymphocyte. T-SUPPRESSOR CELL: a type of T-cell that bears the CD8 surface marker and helps to regulate the immune response. TESTOSTERONE: a steroid hormone produced by the testes, essential for sperm production and the development of reproductive organs and secondary sexual characteristics in males. Testosterone is under study as a therapy for HIV-related wasting syndrome. TH1/TH2 IMMUNE RESPONSE: 2 branches of the immune system. The TH1 response involves a subset of CD4 lymphocytes called TH1 cells that secrete IL-1, IL-2 and gamma interferon, which enhance the cell-mediated immune response. The TH2 response involves the TH2 subset of CD4 cells that secrete IL-4 and IL-10, which enhance the humoral (antibody-based) immune response. THROMBOCYTOPENIA: a condition marked by an abnormally low number of platelets, blood cells that facilitate normal blood clotting; the condition may result in abnormal bleeding and bruising. THRUSH: see candidiasis. THYMUS (adjective THYMIC): a lymphoid organ in the upper chest cavity that is the source of lymphocytes in children, but which generally shrinks during adolescence. The thymus is the site of lymphocyte differentiation where lymphocytes learn to recognize antigens. The thymus produces some 30 hormones or thymic factors (e.g., thymodulin, thymopentin, thymostimulin) that are involved in the regulation of immune function. TOLERANCE: a condition in which the body becomes accustomed to an agent (e.g., drug) so that the previous dose no longer produces the desired effects. TOXICITY (adjective TOXIC): the quality of being poisonous or harmful; often used to refer to side effects of drugs. TOXOPLASMOSIS: an opportunistic infection caused by the microscopic parasite Toxoplasma gondii, found in raw or undercooked meat and cat feces. Symptoms may include headache, lymphadenopathy, malaise, muscle pain, fever and dementia. Toxoplasmosis may lead to brain swelling, coma and death in persons with suppressed immune systems. TRADITIONAL CHINESE MEDICINE (TCM): an Asian system of healing that focuses on achieving internal balance using methods such as acupuncture, heat application (moxibustion), herbal preparations and exercises (e.g., tai chi, qigong) to restore the flow of qi ("vital energy") and the balance of yin and yang. TRANSFORMATION ZONE: the area of the cervix where squamous cells and columnar cells meet; a common site for dysplasia. TREATMENT IND (TIND): an FDA protocol that allows patients with life-threatening disease to obtain experimental drugs through their physician free of charge from the drug's manufacturer. TUBERCULOSIS (TB): an infectious disease caused by Mycobacterium tuberculosis that typically affects the lungs but may occur in other organs (extrapulmonary TB). Transmission generally occurs through inhalation of aerosolized sputum droplets. Multidrug-resistant tuberculosis (MDR-TB) is resistant to some of the standard drugs and requires more aggressive treatment. TUMOR NECROSIS FACTOR (TNF, CACHECTIN): a cytokine produced by activated monocytes and macrophages that can destroy tumors. When chronically elevated, TNF may lead to fever, anorexia, hypermetabolism and wasting. UVEITIS: an inflammation of the membranes (uvea) of the eye. VACCINE: a preparation that contains an infectious agent or its components which is administered to stimulate an immune response that will protect a person from illness due to that agent. A therapeutic (or treatment) vaccine is given after infection and is intended to reduce or arrest disease progression. A preventive vaccine is intended to prevent initial infection. VARICELLA-ZOSTER VIRUS: a virus in the herpes family that causes chickenpox (varicella). VZV may lie dormant for years and reactivate later in life to cause shingles (herpes zoster), especially in immunosuppressed individuals. VECTOR: an agent used as a vehicle for transfer. A disease vector is an agent that transfers a pathogen from one organism to another (e.g., an insect). A viral vector is an engineered virus used to introduce genes into cells or a live virus used as an antigen delivery vehicle in a vaccine. VERTICAL TRANSMISSION (PERINATAL TRANSMISSION, MATERNAL-FETAL TRANSMISSION): the transmission of an infectious organism from a mother to a fetus or neonate (newborn). Vertical transmission may occur in utero (in the womb), during birth or via breastfeeding. VIRAL LOAD (VIRAL BURDEN): the amount of virus in the blood or other tissues. The presence of HIV RNA indicates that the virus is replicating; changes in viral load may be used to gauge drug effectiveness and disease progression. Viral load is measured using assays such as QC-PCR or branched-chain DNA, and is expressed as the number of copies of RNA per milliliter (mL) of blood. VIREMIA: the presence of virus in the blood or plasma. VIRION: a complete virus particle. VIRULENCE (adjective VIRULENT): aggressiveness, ability to cause disease. VIRUS: a group of minute organisms that are unable to grow or reproduce outside the body of a host. During replication a virus integrates its genetic material (DNA or RNA) into a host cell and takes over the cell's biological mechanisms to reproduce new virus particles. VULVA: the external female genitalia, including the clitoris and the inner and outer labia (lips) surrounding the urethral and vaginal openings. WASTING SYNDROME: a condition characterized by atrophy of lean body mass and involuntary weight loss of more than 10% of normal body weight. WILD-TYPE: the normal, typical phenotype of a virus or other organism before genetic mutation or manipulation takes place. Page last updated 23 July 1996 |
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