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Subject: c
Date: Thu, 12 Oct 95 23:34 PDT (495 lines of text)

CACHEXIA:

General ill health and malnutrition, marked by weakness and emaciation, usually associated with serious disease. See also Wasting Syndrome.

CANDIDA:

Yeast-like fungi commonly found in the normal flora of the mouth, skin, intestinal tract and vagina, but can become clinically infectious in immune compromised people. See also Fungus.

CANDIDIASIS:

An infection with a fungus of the Candida family, generally Candida albicans; it most commonly involves the skin (dermatocandidiasis), oral mucosa (thrush), respiratory tract (bronchocandidiasis) and vagina (vaginitis). Candidiasis of the esophagus, trachea, bronchi or lungs is an indicator disease for AIDS. See also Fungus; Thrush.

CARCINOGEN:

Any cancer-producing substance.

CATHETER:

A tubular medical device for insertion into canals, vessels, passageways or body cavities, usually to permit injection (e.g., through an intravenous catheter into a vein) or withdrawal of fluids, or to keep a passage open.

CBCT:

See Community-Based Clinical Trial.

CBO:

See Community-Based Organization.

CDC:

See Centers for Disease Control and Prevention.

CD8 (T8) CELLS:

A protein embedded in the cell surface of suppressor T lymphocytes. Also called cytotoxic T cells. See also CD Nomenclature; CD4 (T4) or CD4+ Cells; T Cells.

CD4 (T4) or CD4+ CELLS:

1. White blood cells killed or disabled during HIV infection. These cells normally orchestrate the immune response, signaling other cells in the immune system to perform their special functions. Also known as T helper cells. 2. HIV's preferred targets are cells that have a docking molecule called cluster designation 4 (CD4) on their surfaces. Cells with this molecule are known as CD4-positive (or CD4+) cells. Destruction of CD4+ lymphocytes is the major cause of the immunodeficiency observed in AIDS, and decreasing CD4+ lymphocyte levels appear to be the best indicator of morbidity in these patients. Although CD4 counts fall, the total T-cell level remains fairly constant through the course of HIV disease, due to a concomitant increase in the CD8+ cells. The ratio of CD4+ to CD8+ cells is therefore an important measure of disease progression. See also CD Nomenclature; CD8 (T8) Cells; Immunodeficiency.

CDC NATIONAL AIDS CLEARINGHOUSE:

The CDC's comprehensive reference, referral and publication distribution service for HIV and AIDS information. The Clearinghouse works in partnership with national, regional, state and local organizations that develop and deliver HIV prevention programs and services.

CD NOMENCLATURE:

This nomenclature was developed to standardize and compare monoclonal antibodies from different sources. Antibodies with similar reactivity patterns are assigned to CD groups representing "clusters of differentiation." T lymphocytes are CD3+ and can be separated into the CD4+ T helper cells and the CD8+ cytotoxic/suppressor cells. Although CD4+ cells are predominantly T lymphocytes, some monocytes are also CD4+.

CELL LINES:

Specific cell types artificially maintained in the laboratory (i.e., in vitro) for scientific purposes.

CELL-MEDIATED IMMUNITY (CMI):

The branch of the immune system in which the reaction to foreign material is performed by specific defense cells (i.e., killer cells, macrophage and other white blood cells) rather than antibodies.

CELLULAR IMMUNITY:

See Cell-Mediated Immunity.

CENTERS FOR DISEASE CONTROL AND PREVENTION (CDC):

A Public Health Service agency responsible (among others) for assessing the status and characteristics of the AIDS epidemic and the prevalence of HIV infections. CDC supports the design, implementation and evaluation of prevention activities, and maintains various HIV/AIDS information services, such as the CDC National AIDS Clearinghouse.

CENTRAL NERVOUS SYSTEM (CNS):

Composed of the brain, spinal cord and its coverings (meninges).

CENTRAL NERVOUS SYSTEM (CNS) DAMAGE:

(By HIV infection). Although monocytes and macrophages can be infected by HIV, they appear to be relatively resistant to killing. However, these cells travel throughout the body and carry HIV to various organs, especially the lungs and the brain. People infected with HIV often experience abnormalities in the central nervous system. Investigators have hypothesized that an accumulation of HIV in brain and nerve cells or the inappropriate release of cytokines or toxic byproducts by these cells may be to blame for the neurological manifestations of HIV disease. See also Cytokines; Macrophage; Monocyte.

CEREBRAL:

Pertaining to the cerebrum, the main portion of the brain.

CERVICAL CANCER:

A neoplasm of the uterine cervix that can be detected in the early curable stage by the Papanicolaou (Pap) test. See also Cervical Dysplasia; Cervix; Pap Smear.

CERVICAL DYSPLASIA:

A precursor lesion for cervical cancer. Studies indicate an increase in prevalence of cervical dysplasia among HIV-infected women. Additional studies have documented that a higher prevalence is associated with greater immuno suppression. HIV infection also may adversely affect the clinical course and treatment of cervical dysplasia and cancer. See also Dysplasia.

CERVICAL INTRAEPITHELIAL NEOPLASIA (CIN1, CIN2, CIN3):

Dysplasia of the cervix epithelium, often pre-malignant (i.e., cancerous), characterized by various degrees of hyperplasia, abnormal keratinization (forming horny epidermal tissue) and condylomata. Considerable evidence implicates human papilloma virus (HPV) in the development of CIN. Immunosuppression may also play an important role in facilitating infection or persistence of HPV in the genital tract and progression of HPV-induced neoplasia. See also Cervix; Condyloma; Dysplasia; Epithelium; Hyperplasia; Neoplasm.

CERVIX:

The part of the uterus that protrudes into the cavity of the vagina. See also Uterus.

CHALLENGE:

In vaccine experiments, the exposure of an immunized animal to the infectious agent.

CHEMOTHERAPY:

The treatment, mostly of cancer, by the use of a series of cytotoxic drugs that attack cancerous cells. This treatment commonly has adverse side effects that may include the temporary loss of the body's natural immunity to infections, loss of hair, digestive upset and a general feeling of illness. Although unpleasant, the adverse effects of treatment are tolerated considering the life-threatening nature of the cancers usually treated by chemotherapy. See also Cytotoxic.

CHRONIC IDIOPATHIC DEMYELINATING POLYNEUROPATHY (CIPD):

Chronic, spontaneous loss or destruction of myelin. Myelin is a soft, white, somewhat fatty material that forms a thick sheath around the protoplasmic core of myelinated nerve fiber.

CIPD:

See Chronic Idiopathic Demyelinating Polyneuropathy.

CIRCULATING IMMUNE COMPLEXES:

See Immune Complex.

CLADE:

A group of related HIV variants, classified according to degree of genetic similarity. HIV variants are currently grouped into clades A, B, C, D, E, F and O.

CLINICAL:

Pertaining to or founded on observation and treatment of patients, as distinguished from theoretical or basic science.

CLINICAL ALERT:

A mechanism, adopted by the National Institutes of Health in onjunction with the editors of several biomedical journals, for urgent cases in which timely and broad dissemination of results of clinical trials could prevent morbidity (sickness) and mortality (death). The Clinical Alert does not become a barrier to subsequent publication of the full research paper. Clinical Alerts are widely distributed electronically through the National Library of Medicine and through standard mailings.

CLINICAL LATENCY:

The state or period of an infectious agent, such as a virus or bacterium, living or developing in a host without producing clinical symptoms. As related to HIV infection:

Although infected individuals usually exhibit a period of clinical latency with little evidence of disease, the virus is never truly latent. Even early in the disease, HIV is active within lymphoid organs where large amounts of virus become trapped in the FDC network. Surrounding germinal centers are areas rich in CD4+ T cells. These cells increasingly become infected and viral particles accumulate both in infected cells and as free virus. See also CD4 (T4) or CD4+ Cells; Lymphoid Organs.

CLINICAL PRACTICE GUIDELINES:

Standards for physicians to adhere to in prescribing care for a given condition or illness.

CLINICAL TRIAL:

A carefully designed and executed investigation of the effects of a drug (or vaccine) administered to human subjects. The goal is to define the clinical efficacy and pharmacological effects (toxicity, side effects, incompatibilities or interactions) of the drug. The US government, through the Food and Drug Administration, requires strict testing of all new drugs and vaccines prior to their approval for use as therapeutic agents.

CLONE:

1. A group of genetically identical cells or organisms descended from a common ancestor. To produce such genetically identical copies. 2. A genetically identical replication of a living cell that is valuable for the investigation and reproduction of test cultures.

CMV:

See Cytomegalovirus.

CNS:

See Central Nervous System.

COCCIDIOIDOMYCOSIS:

An infectious fungal disease caused by the inhalation of spores of Coccidioides immitis, which is carried on windblown dust particles. The disease is endemic in hot dry regions of the Southwestern US and Central and South America, and is an opportunistic disease associated with AIDS. Also called desert fever, San Joaquin fever, valleyfever. See also Fungus; Opportunistic Infection.

COFACTORS:

1. Substances, microorganisms or characteristics of individuals that may influence the progression of a disease or the likelihood of becoming ill. 2. A substance, such as a metallic ion or coenzyme, that must be associated with an enzyme for the enzyme to function. 3. A situation or activity that may increase a person's susceptibility to AIDS. Examples of such cofactors are other infections, drugs and alcohol use, poor nutrition, genetic factors and stress.

COHORT:

In epidemiology, a group of individuals with some characteristics in common.

COLITIS:

Inflammation of the colon.

COMMUNITY-BASED CLINICAL TRIAL (CBCT):

A clinical trial conducted primarily through primary-care physicians rather than academic research facilities.

COMMUNITY-BASED ORGANIZATION (CBO):

A locally based service organization that provides social services at the community level.

COMMUNITY PROGRAMS FOR CLINICAL RESEARCH ON AIDS (CPCRA):

An initiative of the National Institute of Allergy and Infectious Diseases (NIAID) to broaden the base of clinical investigations by involving community physicians in AIDS research and trials. NIAID started the CPCRA in 1989. It is one of four HIV clinical trials programs supported by NIAID. In 1992 the name of the program was officially changed to the Terry Beirn Community Programs for Clinical Research on AIDS. (See also Terry Beirn Community Programs for Clinical Research on AIDS).

COMPASSIONATE USE:

A method of providing experimental drugs to very sick patients who have no other treatment options. Often, case-by-case approval must be obtained from the Food and Drug Administration for "compassionate use" of a drug.

COMPLEMENT:

A group of proteins in normal blood serum and plasma which, in combination with antibodies, causes the destruction of antigens, particularly bacteria and foreign blood corpuscles. See also Antibodies; Antigen.

COMPLEMENT CASCADE:

A precise sequence of events, usually triggered by an antigen-antibody complex, in which each component of the complement system is activated in turn. See also Antibodies; Antigen.

CONCOMITANT DRUGS:

Drugs that are taken together. Certain concomitant medications may have adverse interactions.

CONCORDE STUDY:

Joint French/British clinical trial of AZT in asymptomatic HIV-positive individuals. See also AZT.

CONDYLOMA:

(Condyloma acuminatum). A papilloma with a central core of connective tissue in a treelike structure covered with epithelium, usually occurring on the mucous membrane or skin of the external genitals or in the perianal (tissue surrounding the anus) region. Although the lesions are usually few in number, they may aggregate to form large cauliflower-like masses. Caused by the human papilloma virus (HPV), it is infectious and autoinoculable (i.e., capable of being transmitted by inoculation from one part of the body to another). Also called acuminate or venereal warts. See also Epithelium; Papilloma.

CONTAGIOUS:

Any infectious disease capable of being transmitted by casual contact from one person to another. Casual contact can be defined as normal day-to-day contact between people at home, school, work or in the community. A contagious infection (e.g., a common cold) can be communicable by casual contact; an infectious infection, on the other hand, is communicable by intimate contact such as sex. AIDS is infectious, not contagious.

CONTRAINDICATION:

A specific circumstance when the use of certain treatments could be harmful.

CONTROL:

A standard against which experimental observations may be evaluated. In clinical trials, one group of patients is given an experimental drug, while another group (i.e., the control group) is given either a standard treatment for the disease or a placebo. See also Placebo.

CORE PROTEIN:

As related to HIV:

An integral protein of the HIV virus composed of three units, p24, p15 and p18.

CORRELATES OF IMMUNITY/CORRELATES OF PORTECTION:

The immune responses that protect an individual from a certain disease. The precise identities of the correlates of immunity in HIV are unknown.

CPCRA:

See Community Programs for Clinical Research on AIDS.

CREATININE:

A protein found in muscles and blood, and excreted by the kidneys in the urine. The level of creatinine in the blood and urine provides a measure of kidney function.

CRYPTOCOCCAL MENINGITIS:

A life-threatening infection of the membranes (meninges) that line the brain and the spinal cord. Cryptococcal disease is caused by a fungus (Cryptococcus neoformans). Most people have been exposed to this organism, which is found in soil contaminated by bird droppings, but it usually does not cause disease in healthy people. The majority of people with cryptococcal meningitis have immune systems that are damaged by disease, such as AIDS, or suppressed by drugs. The organism can infect almost all organs of the body, although it most commonly causes disease of the meninges, skin or lungs.

CRYPTOCOCCOSIS:

An infectious disease seen in HIV-infected patients due to the fungus Cryptococcus neoformans, which is acquired via the respiratory tract. It can spread from the lungs to the brain, the central nervous system, the skin, skeletal system and urinary tract. See also Cryptococcal Meningitis.

CRYPTOSPORIDIOSIS:

An opportunistic infection caused by the protozoan parasite Cryptosporidium parvum.

CT:

(Computed Tomography). Radiography (using X-rays) in which a three-dimensional image of a body structure is constructed by computer from a series of plane cross-sectional images made along an axis. Also referred to as CAT scan.

CTL:

See Cytotoxic T Lymphocyte.

CUTANEOUS:

Of, pertaining to or affecting the skin.

CYTOKINES:

1. Immune system proteins involved in the normal regulation of the immune response. They may also help to activate HIV-2. Proteins used for communication by cells of the immune system. Central to the normal regulation of the immune response.

CYTOMEGALOVIRUS (CMV):

A herpes virus that is a common cause of opportunistic diseases in people with AIDS and other people with immune suppression. While CMV can infect most organs of the body, people with AIDS are most susceptible to CMV retinitis (disease of the eye) and colitis (disease of the colon). See also Cytomegalovirus (CMV) Retinitis.

CYTOMEGALOVIRUS (CMV) RETINITIS:

Most adults in the US have been infected by cytomegalovirus, although the virus usually does not cause disease in healthy people. Because the virus remains in the body for life, it can cause disease if the immune system becomes severely damaged by disease or suppressed by drugs. CMV retinitis is an eye disease common among people who are infected with HIV. Without treatment, people with CMV retinitis can lose their vision. CMV infection can affect both eyes and is the most common cause of blindness among people with AIDS.

CYTOPENIA:

Deficiency in the cellular elements of the blood.

CYTOPLASM:

All of the substance of a cell other than the nucleus.

CYTOTOXIC:

An agent or process that is toxic to cells (i.e., it causes suppression of function or cell death).

CYTOTOXIC T LYMPHOCYTE (CTL):

A lymphocyte that is able to kill foreign cells that have been marked for destruction by the cellular immune system. See also CD8 (T8) Cells; Lymphocyte.