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SALMONELLA:
A family of gram-negative bacteria, found in undercooked poultry or eggs, that are a common cause of food poisoning, and that can cause serious disseminated disease in HIV-positive persons.

SALVAGE THERAPY:
A treatment effort for people who are not responding to, or cannot tolerate the preferred, recommended treatments for a particular condition. In the context of HIV infection, drug treatments that are used or studied in individuals who have failed one or more HIV drug regimens, including protease inhibitors. In this case, failed refers to the inability to achieve and sustain low viral load levels.

SAMHSA:
See Substance Abuse and Mental Health Services Administration.

SAQUINAVIR:
1. An FDA approved (12/07/95) hard-gel capsule protease inhibitor for combination use with nucleoside analogs for the treatment of HIV infection. Also called Invirase. 2. An FDA approved (11/07/97) soft-gel capsule protease inhibitor for use in combination with other antiretroviral agents for the treatment of HIV infection. Also called Fortovase.

SARCOMA:
A malignant (cancerous) tumor of the skin and soft tissue.

SEBORRHEIC DERMATITIS:
A chronic inflammatory disease of the skin of unknown 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. Seborrheic dermatitis in patients infected with HIV responds to a variety of therapies but tends to reoccur. Topic antifungal agents and corticosteroids suppress the process, but therapy must be applied repeatedly.

SEPSIS:
The presence of harmful microorganisms or associated toxins in the blood.

SEROCONVERSION:
The development of antibodies to a particular antigen. When people develop antibodies to HIV, they "seroconvert" from antibody-negative to antibody-positive. It may take from as little as 1 week to several months or more after infection with HIV for antibodies to the virus to develop. After antibodies to HIV appear in the blood, a person should test positive on antibody tests. See Incubation Period; Window Period.

SEROLOGIC TEST:
Any of a number of tests that are performed on the clear portion of blood (see serum). Often refers to a test that determines the presence of antibodies to antigens such as viruses.

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 Serum.

SEROSTATUS:
Results of a blood test for specific antibodies.

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

SEXUALLY TRANSMITTED DISEASE (STD):
Also called venereal disease (VD) (an older public health term) or sexually transmitted infections (STIs). Sexually transmitted diseases are infections spread by the transfer of organisms from person to person during sexual contact. In addition to the "traditional" STDs (syphilis and gonorrhea), the spectrum of STDs now includes HIV infection, which causes AIDS; Chlamydia trachomatis infections; human papilloma virus (HPV) infection; genital herpes; chancroid; genital mycoplasmas; hepatitis B; trichomoniasis; enteric infections; and ectoparasitic diseases (i.e., diseases caused by organisms that live on the outside of the host's body). The complexity and scope of STDs have increased dramatically since the 1980s; more than 20 organisms and syndromes are now recognized as belonging in this category.

SF-2:
A strain of HIV used in vaccine development.

SGOT:
(Serum Glutamic Oxaloacetic Transaminase.) Also known as AST (aspartate aminotransaminase), a liver enzyme that plays a role in protein metabolism, such as SGPT. Elevated serum levels of SGOT are a sign of liver damage from disease or drugs.

SGPT:
(Serum Glutamic Pyruvate Transaminase.) Also known as ALT (alanine aminotransaminase), a liver enzyme that plays a role in protein metabolism like SGOT. Elevated serum levels of SGPT are a sign of liver damage from disease or drugs.

SHINGLES:
See Herpes Varicella Zoster Virus.

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

SIDE EFFECTS:
The actions or effects of a drug (or vaccine) other than those 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 non-human primates.

SINUSITIS:
Inflammation of the nasal cavity and sinuses.

SIV:
See Simian Immunodeficiency Virus.

SPECIAL PROJECTS OF NATIONAL SIGNIFICANCE (SPNS):
The SPNS Program is the research and demonstration program of the Ryan White C.A.R.E. Act. The program's mission is to advance knowledge and skills in health and support services for persons with HIV/AIDS. The authorizing legislation specifies three objectives for this program: (1) to assess the effectiveness of particular models of care, (2) to support innovative program design, and (3) to promote replication of effective models.

SPINAL TAP:
See Lumbar Puncture.

SPLEEN:
Large lymphatic organ in the upper left of the abdominal cavity with several functions: (1) trapping of foreign matter in the blood, (2) destruction of degraded red blood cells and foreign matter by macrophages, (3) formation of new lymphocytes and antibody production, and (4) storage of excess red blood cells.

SPLENOMEGALY:
An enlarged spleen.

SPUTUM ANALYSIS:
Method of detecting certain infections (especially tuberculosis) by culturing of sputum -- the mucus matter that collects in the respiratory and upper digestive passages and is expelled by coughing.

STANDARDS OF CARE:
Treatment regimen or medical management based on state-of-the-art patient care.

STAPHYLOCOCCUS:
Type of bacteria that may cause various types of infections.

STAVUDINE:
A nucleoside reverse transcriptase inhibitor first approved by FDA in 1994 and used for the treatment of adults and children with HIV infection who have undergone prolonged prior AZT therapy. Also called d4T, Zerit.

STD:
See Sexually Transmitted Disease.

STEM CELLS:
Cells from which all blood cells derive. Bone marrow is rich in stem cells. Clones of stem cells may become any one of the repertoires of immune cells depending upon which cytokines and hormones they are exposed to.

STERILIZING IMMUNITY:
An immune response that completely eliminates an infection.

STEROID:
Member of a large family of structurally similar lipid substances. Steroid molecules have a basic skeleton consisting of four interconnected carbon rings. Different classes of steroids have different functions. All the natural sex hormones are steroids. Anabolic steroids increase muscle mass. Antiinflammatory steroids (or corticosteroids) can reduce swelling, pain, and other manifestations of inflammation.

STEVENS-JOHNSON SYNDROME:
A severe and sometimes fatal form of erythema multiforme that is characterized by severe skin manifestations; conjunctivitis (eye inflammation), which often results in blindness; Vincent's angina (trench mouth); and ulceration of the genitals and anus.

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

STRAIN:
Subgroup of a species (also called taxon).

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

SUBSTANCE ABUSE AND MENTAL HEALTH SERVICES ADMINISTRATION (SAMHSA):
An agency of the U.S. Department of Health and Human Services. SAMHSA's mission within the Nation's health system is to improve the quality and availability of prevention, treatment, and rehabilitation services in order to reduce illness, death, disability, and cost to society resulting from substance abuse and mental illnesses. Internet address: http://www.samhsa.gov/.

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

SULFA DRUG:
A sulfonamide drug used to treat bacterial infections. These drugs inhibit the action of p-aminobenzoic acid, a substance bacteria need in order to reproduce. Sulfa drugs are now used primarily in the treatment of urinary tract infections and ulcerative colitis. In the HIV area, the sulfa drug, sulfadiazine, is used in combination with pyrimethamine as standard therapy for toxoplasmosis. Trimethoprim is used in combination with another sulfa drug, sulfamethoxazole against PCP.

SULFONAMIDES:
Synthetic derivatives of p-aminobenzenesulfonamide. See Sulfa Drug.

SUPERANTIGEN:
Investigators have proposed that a molecule known as a superantigen, made by either 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 Antigen.

SUPPRESSOR PHENOMENON:
Process where CD8+ cells not only kill HIV-infected cells directly by a process called cytolysis, but also secrete soluble factors that suppress HIV replication in both blood and lymph nodes. It appears that CD8+ cells secrete signaling molecules, called beta-chemokines (see chemokines), which normally recruit inflammatory cells to the site of an infection. Three of these beta-chemokines, RANTES, MIP-1a, and MIP-1b, appear to block HIV replication by occupying receptors necessary for the entry of some strains of HIV into their target cells.

SUPPRESSOR T CELLS:
(T8, CD8.) Subset of T cells that halts antibody production and other immune responses.

SURROGATE MARKER:
Laboratory tests that may predict a patient's clinical outcome or indicate whether a drug is effective without having to rely on the traditional clinical endpoints of death or development of a major opportunistic infection. See CD4 (T4) or CD4+ Cells; CD8 (T8) Cells.

SURVEILLANCE:
See Epidemiologic Surveillance.

SUSCEPTIBLE:
Vulnerable or predisposed to a disease.

SUSTIVA:
See Efavirenz.

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 as reported by the patient and signs as detected in an examination that together are characteristic of a specific condition.

SYNERGISM, SYNERGISTIC:
An interaction between two or more treatments (e.g., drugs) that produces or enhances an effect that is greater than the sum of the effects produced by the individual treatments.

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 -- primarily sexually transmitted -- resulting from infection with the spirochete (a bacterium), Treponema pallidum. Syphilis can also be acquired in the uterus during pregnancy.

SYSTEMIC:
Concerning or affecting the body as a whole. A systemic therapy is one that the entire body is exposed to, rather than just the target tissues affected by a disease.