AIDS Dementia Complex: A neurologic condition associated with the ACQUIRED IMMUNODEFICIENCY SYNDROME and characterized by impaired concentration and memory, slowness of hand movements, ATAXIA, incontinence, apathy, and gait difficulties associated with HIV-1 viral infection of the central nervous system. Pathologic examination of the brain reveals white matter rarefaction, perivascular infiltrates of lymphocytes, foamy macrophages, and multinucleated giant cells. (From Adams et al., Principles of Neurology, 6th ed, pp760-1; N Engl J Med, 1995 Apr 6;332(14):934-40)Peptide T: N-(N-(N(2)-(N-(N-(N-(N-D-Alanyl L-seryl)-L-threonyl)-L-threonyl) L-threonyl)-L-asparaginyl)-L-tyrosyl) L-threonine. Octapeptide sharing sequence homology with HIV envelope protein gp120. It is potentially useful as antiviral agent in AIDS therapy. The core pentapeptide sequence, TTNYT, consisting of amino acids 4-8 in peptide T, is the HIV envelope sequence required for attachment to the CD4 receptor.Dementia: An acquired organic mental disorder with loss of intellectual abilities of sufficient severity to interfere with social or occupational functioning. The dysfunction is multifaceted and involves memory, behavior, personality, judgment, attention, spatial relations, language, abstract thought, and other executive functions. The intellectual decline is usually progressive, and initially spares the level of consciousness.Acquired Immunodeficiency Syndrome: An acquired defect of cellular immunity associated with infection by the human immunodeficiency virus (HIV), a CD4-positive T-lymphocyte count under 200 cells/microliter or less than 14% of total lymphocytes, and increased susceptibility to opportunistic infections and malignant neoplasms. Clinical manifestations also include emaciation (wasting) and dementia. These elements reflect criteria for AIDS as defined by the CDC in 1993.HIV-1: The type species of LENTIVIRUS and the etiologic agent of AIDS. It is characterized by its cytopathic effect and affinity for the T4-lymphocyte.Zidovudine: A dideoxynucleoside compound in which the 3'-hydroxy group on the sugar moiety has been replaced by an azido group. This modification prevents the formation of phosphodiester linkages which are needed for the completion of nucleic acid chains. The compound is a potent inhibitor of HIV replication, acting as a chain-terminator of viral DNA during reverse transcription. It improves immunologic function, partially reverses the HIV-induced neurological dysfunction, and improves certain other clinical abnormalities associated with AIDS. Its principal toxic effect is dose-dependent suppression of bone marrow, resulting in anemia and leukopenia.Cycas: A plant genus of the family Cycadaceae, order Cycadales, class Cycadopsida, division CYCADOPHYTA of palm-like trees. It is a source of CYCASIN, the beta-D-glucoside of methylazoxymethanol.Brain: The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.HIV Envelope Protein gp120: External envelope protein of the human immunodeficiency virus which is encoded by the HIV env gene. It has a molecular weight of 120 kDa and contains numerous glycosylation sites. Gp120 binds to cells expressing CD4 cell-surface antigens, most notably T4-lymphocytes and monocytes/macrophages. Gp120 has been shown to interfere with the normal function of CD4 and is at least partly responsible for the cytopathic effect of HIV.Amino Acids, DiaminoDementia, Vascular: An imprecise term referring to dementia associated with CEREBROVASCULAR DISORDERS, including CEREBRAL INFARCTION (single or multiple), and conditions associated with chronic BRAIN ISCHEMIA. Diffuse, cortical, and subcortical subtypes have been described. (From Gerontol Geriatr 1998 Feb;31(1):36-44)HIV Core Protein p24: A major core protein of the human immunodeficiency virus encoded by the HIV gag gene. HIV-seropositive individuals mount a significant immune response to p24 and thus detection of antibodies to p24 is one basis for determining HIV infection by ELISA and Western blot assays. The protein is also being investigated as a potential HIV immunogen in vaccines.