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Subject: s
Date: Thu, 12 Oct 95 23:34 PDT (246 lines of text)

SEBORRHEIC DERMATITIS:

A chronic inflammatory disease of the skin of unknown etiology (i.e., cause or origin), characterized by moderate erythema; dry, moist or greasy scaling; and yellow crusted patches on various areas, including the mid-parts of the face, ears, supraorbital regions (above the orbit of the eye), umbilicus (the navel), genitalia, and especially the scalp. See also Erythematous.

SEROCONVERSION:

The development of antibodies to a particular antigen. When people develop antibodies to HIV or an experimental HIV vaccine, they "seroconvert" from antibody-negative to antibody-positive. See also Antibodies; Antigen.

SEROLOGIC TEST:

Any of a number of tests that are performed on the clear portion of blood (serum). Often refers to a test that determines the presence of antibodies to antigens such as viruses. See also Antibodies; Antigen; Serum.

SEROPREVALENCE:

As related to HIV infection:

The proportion of persons who have serologic (i.e., pertaining to serum) evidence of HIV infection at any given time. See also Serum.

SEROSTATUS:

Results of a test for specific antibodies. See also Antibodies.

SERUM:

The clear, thin and sticky fluid portion of the blood that remains after coagulation. Serum contains no blood cells, platelets or fibrinogen.

SEXUALLY TRANSMITTED DISEASE (STD):

Also called venereal disease. A contagious disease usually acquired by sexual intercourse or genital contact. Historically, the five venereal diseases were:

gonorrhea, syphilis, chancroid, granuloma inguinale and lymphogranuloma venereum. To these have been added scabies, herpes genitalis and anorectal herpes and warts, pediculosis, trichomoniasis, genital candidiasis, molluscum contagiosum, nonspecific urethritis, chlamydial infections, cytomegalovirus and AIDS. See also Herpes Simplex Virus II; Molluscum Contagiosum.

SF-2:

A strain of HIV used in vaccine development.

SHINGLES:

See Herpes Varicella Zoster Virus.

SHIV:

Genetically engineered hybrid virus having an HIV envelope and an SIV core. See also Genetic Engineering; Hybrid; Simian Immunodeficiency Virus.

SIDE EFFECTS:

The action or effect of a drug (or vaccine) other than that desired. The term usually refers to undesired or negative effects, such as headache, skin irritation or liver damage. Experimental drugs must be evaluated for both immediate and long-term side effects.

SIMIAN IMMUNODEFICIENCY VIRUS (SIV):

An HIV-like virus that infects monkeys, chimpanzees and other nonhuman primates.

SIV:

See Simian Immunodeficiency Virus.

SPINAL TAP:

See Lumbar Puncture.

SPLENOMEGALY:

An enlarged spleen.

STANDARDS OF CARE:

Treatment regimen or medical management based on state-of-the-art patient care.

STATISTICAL SIGNIFICANCE:

A term based on statistical tests that is used to denote the probability that the observed association could have occurred by chance alone. Does not refer to medical or biological significance of an association. For example, a statistical significance at the 1-percent level indicates a 1-in-100 chance that a result can be ascribed to chance.

STD:

See Sexually Transmitted Disease.

STEM CELLS:

Cells from which all blood cells derive. Bone marrow is rich in stem cells.

STERILIZING IMMUNITY:

An immune response that completely eliminates an infection.

STEVENS-JOHNSON SYNDROME:

A severe and sometimes fatal form of erythema multiforme that is characterized by conjunctivitis (eye inflammation) and often results in blindness, Vincent's angina (trench mouth) and ulceration of the genitals and anus. See also Erythema Multiforme.

STOMATITIS:

Any of numerous inflammatory diseases of the mouth having various causes, such as mechanical trauma, irritants, allergy, vitamin deficiency or infection.

STRATIFICATION:

A layered configuration.

SUBARACHNOID SPACE:

The space through which the spinal fluid circulates.

SUBCLINICAL INFECTION:

An infection, or phase of infection, without readily apparent symptoms or signs of disease.

SUBCUTANEOUS:

Beneath or introduced beneath the skin (e.g., subcutaneous injections).

SUBUNIT HIV VACCINE:

A genetically engineered vaccine that is based on only part of the HIV molecule. See also Genetic Engineering.

SULFA DRUG:

Any of a class of synthetic chemical substances derived from sulfanilamide and used to treat bacterial infections. These drugs inhibit the action of para-aminobenzoic acid, a substance bacteria needed in order to reproduce. Sulfa drugs are used primarily in the treatment of urinary tract infections and ulcerative colitis. Antibiotics have largely replaced them in the treatment of other bacterial infections.

SULFONAMIDES:

See Sulfa Drug.

SUPERANTIGEN:

Investigators have proposed that a molecule known as a superantigen, either made by HIV or an unrelated agent, may stimulate massive quantities of CD4+ T cells at once, rendering them highly susceptible to HIV infection and subsequent cell death. See also Antigen; CD4 (T4) or CD4+ Cells.

SUPPRESSOR T CELLS:

(T8, CD8). Subset of T cells that halt antibody production and other immune responses. See also Antibodies; T Cells.

SURROGATE MARKER:

A substitute; a person or thing that replaces another. In HIV disease, the number of CD4+ T cells and CD8+ cells is a surrogate immunological marker of disease progression. See also CD4 (T4) or CD4+ Cells; CD8 (T8) Cells.

SURVEILLANCE:

Close or continuous observation or testing (e.g., serosurveillance), used, among others, in epidemiology. Immunological surveillance, or immunosurveillance, is a monitoring process of the immune system that detects and destroys neoplastic (e.g., cancerous) cells and that tends to break down in immunosuppressed individuals. See also Epidemiologic Surveillance.

SUSCEPTIBLE:

Vulnerable or predisposed to a disease.

SYMPTOMS:

Any perceptible, subjective change in the body or its functions that indicates disease or phases of disease, as reported by the patient.

SYNCYTIA:

("Giant Cells"). Dysfunctional multicellular clumps formed by cell-to-cell fusion. Cells infected with HIV may also fuse with nearby uninfected cells, forming balloonlike giant cells called syncytia. In test tube experiments, these giant cells have been associated with the death of uninfected cells. The presence of so-called syncytia-inducing variants of HIV has been correlated with rapid disease progression in HIV-infected individuals.

SYNDROME:

A group of symptoms and diseases that together are characteristic of a specific condition.

SYNERGISM/SYNERGISTIC:

An interaction between two or more agents (drugs) that produces or enhances an effect that is greater than the sum of the effects produced by the individual agents.

SYNTHESIS:

1. In chemistry, the formation of a compound from simpler compounds or elements. 2. The production of a substance (e.g., as in protein synthesis) by the union of chemical elements, groups or simpler compounds, or by the degradation (i.e., breaking down) of a complex compound.

SYPHILIS:

A disease (usually sexually transmitted) resulting from infection with the spirochete (a bacterium) Treponema pallidum.