FALLOPIAN TUBES:
Part of the female reproductive system. A pair of ducts opening at one end into the uterus and at the other end into the peritoneal cavity, over the ovary. Each tube serves as a passage through which the ovum (egg) is carried to the uterus and through which spermatozoa (sperm) move out toward the ovary.
FDA:
See Food and Drug Administration.
FDC:
See Follicular Dendritic Cells.
FLOATERS:
Drifting dark spots within the field of vision. Floaters can be caused by infection with Cytomegalovirus (CMV) retinitis, but also can appear in persons as a normal part of the aging process.
FOLIC ACID:
A crystalline vitamin of the B complex that is used especially in the treatment of nutritional anemias. It occurs in green plants, fresh fruit, liver, and yeast. Also called folacin, folate, and vitamin B9.
FOLINIC ACID:
Also called citrovorum factor. A metabolically active form of folic acid that has been used in cancer therapy to protect normal cells against methotrexate -- a cancer chemotherapy agent. Also used to treat megaloblastic anemias.
FOLLICLE:
A small anatomical sac, cavity, or deep narrow-mouthed depression (e.g., a hair follicle).
FOLLICULAR DENDRITIC CELLS (FDCs):
Cells found in the germinal centers of lymphoid organs. FDCs have thread-like tentacles that form a weblike network to trap invaders and present them to other cells of the immune system for destruction. See Lymphoid Organs.
FOMITE:
An inanimate object that can harbor pathogenic microorganisms and thus serve as an agent of transmission of an infection.
FOOD AND DRUG ADMINISTRATION (FDA):
The U.S. Department of Health and Human Services agency responsible for ensuring the safety and effectiveness of all drugs, biologics, vaccines, and medical devices, including those used in the diagnosis, treatment, and prevention of HIV infection, AIDS, and AIDS-related opportunistic infections. The FDA also works with the blood banking industry to safeguard the nation's blood supply. Internet address: http://www.fda.gov/.
FORTOVASE:
See Saquinavir.
FUNCTIONAL ANTIBODY:
An antibody that binds to an antigen and has an effect. For example, neutralizing antibodies inactivate HIV or prevent it from infecting other cells.
FUNGUS:
1. One of a group of primitive, nonvascular organisms including mushrooms, yeasts, rusts, and molds. 2. Fungi, which were once classified as plants, have since been reclassified as unmoving organisms that lack chlorophyll. Some fungi are single-celled but differ from bacteria in that they have a distinct nucleus and other cellular structures. Reproduction is accomplished by spores. Mycologists (scientists working with fungi) estimate that there are 100,000 species of fungi, ranging from baker's yeast to dermatophytes (fungi that cause ringworm and athlete's foot) to potentially invasive species such as Candida albicans and Aspergillus. As many as 150 of these organisms have now been linked to animal or human diseases.
FUSIN:
(See CXCR4).
FUSION INHIBITOR:
A class of antiretroviral agents that binds to the gp41 envelope protein and blocks the structural changes necessary for the virus to fuse with the host CD4 cell. When the virus cannot penetrate the host cell membrane and infect the cell, HIV replication within that host cell is prevented.
FUSION MECHANISM:
Fusion is an integral step in the process whereby HIV enters cells. Researchers have found that in addition to the primary receptor, the CD4 molecule, other cofactors, such as CCR5 and CXCR4, are needed in order for HIV to fuse with the membranes of the immune system cells.
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