Hiv aids là gì? Các công bố khoa học về Hiv aids

The chemokine receptor 5 (CKR5) protein serves as a secondary receptor on CD4 ⁺ T lymphocytes for certain strains of human immunodeficiency virus-type 1 (HIV-1). The CKR5 structural gene was mapped to human chromosome 3p21, and a 32-base pair deletion allele ( CKR5Δ32 ) was identified that is present at a frequency of ∼0.10 in the Caucasian population of the United States. An examination of 1955 patients included among six well-characterized acquired immunodeficiency syndrome (AIDS) cohort studies revealed that 17 deletion homozygotes occurred exclusively among 612 exposed HIV-1 antibody-negative individuals (2.8 percent) and not at all in 1343 HIV-1-infected individuals. The frequency of CKR5 deletion heterozygotes was significantly elevated in groups of individuals that had survived HIV-1 infection for more than 10 years, and, in some risk groups, twice as frequent as their occurrence in rapid progressors to AIDS. Survival analysis clearly shows that disease progression is slower in CKR5 deletion heterozygotes than in individuals homozygous for the normal CKR5 gene. The CKR5Δ32 deletion may act as a recessive restriction gene against HIV-1 infection and may exert a dominant phenotype of delaying progression to AIDS among infected individuals.

The Tuskegee study of untreated syphilis in the Negro male is the longest nontherapeutic experiment on human beings in medical history. The strategies used to recruit and retain participants were quite similar to those being advocated for HIV/AIDS prevention programs today. Almost 60 years after the study began, there remains a trail of distrust and suspicion that hampers HIV education efforts in Black communities. The AIDS epidemic has exposed the Tuskegee study as a historical marker for the legitimate discontent of Blacks with the public health system. The belief that AIDS is a form of genocide is rooted in a social context in which Black Americans, faced with persistent inequality, believe in conspiracy theories about Whites against Blacks. These theories range from the belief that the government promotes drug abuse in Black communities to the belief that HIV is a manmade weapon of racial warfare. An open and honest discussion of the Tuskegee Syphilis Study can facilitate the process of rebuilding trust between the Black community and public health authorities. This dialogue can contribute to the development of HIV education programs that are scientifically sound, culturally sensitive, and ethnically acceptable.

BACKGROUND. The number of reported cases of acquired immune deficiency syndrome (AIDS) is increasing disproportionately among Blacks in the United States. The relatively high incidence of sexually transmitted diseases among Black adolescents suggest the need for AIDS prevention programs to reduce their risk of sexually transmitted human immunodeficiency virus (HIV) infection. METHODS. Black male adolescents (n = 157) were randomly assigned to receive an AIDS risk reduction intervention aimed at increasing AIDS-related knowledge and weakening problematic attitudes toward risky sexual behavior, or to receive a control intervention on career opportunities. RESULTS. The adolescents who received the AIDS intervention subsequently had greater AIDS knowledge, less favorable attitudes toward risky sexual behavior, and lower intentions to engage in such behavior than did those in the control condition. Follow-up data collected 3 months later revealed that the adolescents who had received the AIDS intervention reported fewer occasions of coitus, fewer coital partners, greater use of condoms, and a lower incidence of heterosexual anal intercourse than did the other adolescents. CONCLUSIONS. These results suggest that interventions that increase knowledge about AIDS and change attitudes toward risky sexual behavior may have salutary effects on Black adolescents' risk of HIV infection.

Activated monocytes release a number of substances, including inflammatory cytokines and eicosanoids, that are highly toxic to cells of the central nervous system. Because monocytic infiltration of the central nervous system closely correlates with HIV-1-associated dementia, it has been suggested that monocyte-derived toxins mediate nervous system damage. In the present study, we show that the HIV-1 transactivator protein Tat significantly increases astrocytic expression and release of monocyte chemoattractant protein-1 (MCP-1). Astrocytic release of β-chemokines, which are relatively less selective for monocytes, including RANTES, macrophage inflammatory protein-1α, and macrophage inflammatory protein-1β, was not observed. We also show that MCP-1 is expressed in the brains of patients with HIV-1-associated dementia and that, of the β-chemokines tested, only MCP-1 could be detected in the cerebrospinal fluid of patients with this condition. Together, these data provide a potential link between the presence of HIV-1 in the brain and the monocytic infiltration that may substantially contribute to dementia.