摘要:

Summary:Ninety-seven isolates of human immunodeficiency virus (HIV) from 73 individuals were assayed for susceptibility to zidovudine (AZT). All isolates from 41 individuals with no known therapy with zidovudine were uniformly susceptible to the drug in vitro. In contrast to isolates from subjects with AIDS or AIDS-related complex, isolates from subjects with fewer signs and symptoms or high CD4 lymphocyte counts developed reduced susceptibility at slower rates and lower levels of resistance. Patients receiving lower doses of zidovudine at both early and late stages of disease did not develop resistance more readily than patients receiving higher doses of drug.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:Four-color cell surface immunofluorescence and flow cytometry analysis was used to quantitate mononuclear cell subpopulations from HIV seropositive (HIV+) and seronegative (HIV-) homosexual men and heterosexual men. HIV+men were divided into two groups based on peripheral blood CD4/mm3of >500 or <500. CD4+cells that were simultaneously CD45R-, CDw29-, and 13-were significantly less in HIV+men with <500 CD4/mm3(17%) compared to heterosexual men (34%). This lower percentage of “CD4 only” cells in HIV+males with <500 CD4/mm3correlated with a significantly higher percentage of CD4+cells that were CD45R+, CDw29+, and 13+in these individuals. CD8+cells that were CD45R+, 13+, but CD38-, were significantly less in HIV+men with <500 CD4 as compared to HIV-homosexual men. In contrast, a second CD8+subpopulation that was CD45R-, CD38+, and either 13+or 13-was significantly greater in <500 HIV+men as compared to both HIV-homosexual men and heterosexual men. A significant difference in this subpopulation was observed between the <500 and >500 HIV+groups and correlated with seropositivity for viral p24 antigen. Interestingly, CD8+cells that were CD45R+, as well as CD38+, and either 13+or 13-were significantly greater in the <500 HIV+group compared to the >500 HIV+group, and did not correlate with p24 seropositivity. The percentage of monocyte/macrophages that were CD4-or expressed dim CD4 immunofluorescence, but were 13+, was significantly greater in HIV+men (43%) compared to HIV-homosexual men (27%). In summary, we have identified previously undescribed mononuclear cell subpopulations that were altered with HIV infection and, in some cases, correlated with the stage of disease.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:Neurobehavioral functioning and magnetic resonance imaging (MRI) were investigated in 25 patients with various Centers for Disease Control (CDC) stages of human immunodeficiency virus (HIV) infection and in a control group of seven normal subjects. Unequivocal slowing of information processing speed and cerebral atrophy were related to the stage of HIV infection, with patients in CDC group IV exhibiting the most abnormal findings. Slowing of response speed was directly related to the severity of cerebral atrophy.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:An analysis is presented of sexual behaviour data from a “random‘’ sample (n= 780) of the adult population of England and Wales. Sex stratified frequency distributions of the reported number of sex partners/time were analysed for heterosexuals, demographic characteristics associated with the number of sex partners/time were identified, and epidemiological parameters (the basic reproductive rate of HIV and the doubling time of the epidemic) were calculated. These analyses suggest that the size of the group at risk for acquiring the virus by heterosexual transmission may be large and that the age of first sexual intercourse (for males and females) is decreasing in younger cohorts. Members of the potential heterosexual at-risk group may be identified by demographic variables such as marital status (males and females) and age (females only), but not by socioeconomic class. The epidemiological implications of our results for the heterosexual transmission of HIV are discussed.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:Recent reports have suggested that HSV-2 infection and associated anogenital ulcerations represent an important risk factor for acquisition of HIV infection. Although this is an appealing biological hypothesis, inferences drawn for homosexual men, as well as other at-risk populations, must be made after careful consideration of methods to control for potential confounding data. This report utilized a nested case-control study in which 49 homosexual HIV seroconverters were compared to 49 homosexual seronegative men matched on the prior level of receptive anal intercourse. No differences were observed for prior HSV-2 infection, since 21/49 (43%) of matched HIV seronegative men were HSV-2 antibody positive and 21/49 (43%) of HIV seroconverters were HSV-2 antibody positive at the visit 6 months before HIV seroconversion (odds ratio of 1.0, 95% confidence limits of 0.3–2.9) Similar findings were also observed for prior HSV-1 infection. Both self-reported symptoms and physical exam findings suggestive of HSV infection were rare during the 12 months prior to seroconversion and not associated with HIV seroconversion. These data do not support HSV-2 as a risk factor for seroconversion to HIV among homosexual men studied. These results should not be generalized to heterosexual transmission of HIV, particularly in Africa, where both an increased-prevalence of genital ulcerative diseases and different etiologies have been observed.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:A seroepidemiological study was carried out to determine the distribution of the human immunodeficiency viruses type 1 (HIV-1) and type 2 (HIV-2) in the People's Republic of Angola, where HIV-2 existence was previously unknown and HIV-1 seropositivity was only reported to be present in Luanda and Cabinda. A total of 1,695 serum samples were obtained from healthy persons (control group) and from a group of patients in the provinces of Zaire (13), Lunda-Norte (L.N.) (749), Luanda (556), Huambo (154), Kuando-Kubango (K.-K.) (49), and Namibe (119). All samples were tested for HIV-1 and HIV-2 antibodies by enzyme-linked immunosorbent assay and an indirect immunofluorescence assay using MOLT-T4 cells. Positive samples were confirmed by the Western-blot technique. Sera giving cross reactivity at the level of HIV-1 and HIV-2 large glycoproteins were further tested by radioimmunoprecipitation assay and by reactivity against a peptide corresponding to the dominant epitope of the transmembrane protein. The overall sero-prevalence was 14.2%, with significantly higher values in the patient group [19.4% (HIV-1 = 8.8%; HIV-2 = 8.4%; HIV-1 + HIV-2 = 2.2%)] than the control group [9.3% (HIV-1 = 3.3%; HIV-2 = 5.3%; HIV-1 + HIV-2 = 0.7%)]. HIV-2 as well as HIV-1 infection is actually present in Angola in all studied provinces. Higher seroprevalence was seen in the provinces of Zaire, Lunda Norte, and Huambo. People displacements, mainly as a consequence of the war, certainly play an important role in spreading HIV infection from the northern frontier areas of the country to the central and southern regions.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:Zidovudine (3′-azido-3′-deoxythymidine; AZT) inhibited replication of an immunodeficiency-inducing strain of feline leukemia virus (FeLV-FAIDS) in vitro at concentrations of 0.5–0.005 μg/ml. A 25–30% additional antiviral effect was achieved in vitro when AZT was combined with human recombinant alpha interferon 2a (IFNα). Oral administration of AZT (20 mg/kg three times daily) to cats resulted in plasma concentrations of 3 μg/ml at 2 h post-administration with a T1/2of approximately 1.60 h. Administration of AZT alone or in combination with IFNα or interleukin-2 (IL-2) throughout a 6-week treatment period enabled cats to resist challenge with FeLV-FAIDS. In contrast, those cats treated with IFNα or IL-2 alone became persistently antigenemic (core protein p27) in parallel with placebo-treated controls. Antigenemia remained undetectable in AZT-treated cats throughout an 80-day period post-inoculation (38 days after treatment was withdrawn). However, latent FeLV-FAIDS in bone marrow was detectable by in vitro culture of progenitor cells in the presence of hydrocortisone. Serial analysis of circulating p27 antigen, neutralizing antibody, and quantification of latent, reactivatable virus indicated that those animals receiving AZT in combination with IFNα were most able to resist FeLV-FAIDS challenge. This work provides additional evidence that early presymptomatic treatment employing combination chemoimmunotherapy can be effective in medical intervention of retroviral infection.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:Thenefgene has been reported to be a silencer of human immunodeficiency virus (HIV) transcription that requires the presence of the negative regulatory element (NRE) located at the 5′ end of the HIV long terminal repeat (LTR) to exert its negative effect. We have examined nuclear extracts from human, nontransformed T cells for factors that bind to the NRE of HIV-1 and to determine whether binding of factors to this region can be affected by thenefgene. Using gel retardation and methylation interference assays, we have observed several DNA binding factors that bind to a region between nucleotides −315 and −240 upstream of the cap site, within the NRE segment of the 5′ LTR. Furthermore, the precise locations of the binding sites for two of these factors, termed here A1and R, were determined. Factor A1appears to belong to a family of cellular activation associated factors (called here A1-A4), but it is distinct in that it is the only DNA binding factor so far observed that appears to be downregulated by thenefgene or its product and that it has been found only in cells undergoing lymphokine-driven cell division. In contrast to the A factors, factor R appears to be associated with cellular quiescence and binds to a nearby but distinct site in the NRE. Experiments in which extracts were mixed before gel retardation suggest that the binding of factors R and A1are mutually exclusive. Based on these observations we propose a model in which thenefgene aids in the maintenance of HIV latency by downregulating the binding of proliferation associated DNA binding factor, which we have called A1.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:Neutralizing antibodies (NAs) against four isolates of human immunodeficiency virus type 1 (HIV-1) were assayed in HIV-1 antibody positive sera from the United States, Haiti, Zimbabwe, and Zaire. Overall, there were NAs detected in 95, 81, 60, and 73% of sera with reciprocal geometric mean titers (GMTs) of 626, 23, 10, and 20, respectively, against HIV-1MN, HIV-1IIIB, HIV-1RF, and HIV-1Z3. Sera from North America had significantly higher NA titers against HIV-1MN. In each country, the highest antibody titers observed were against the MN strain. Otherwise, sera from the U.S. neutralized most strongly HIV-1IIIB, sera from Zaire neutralized most strongly HIV-1Z3, and sera from Zimbabwe had equal titers against all three viruses. The differences between countries were reflected in analyses of NA titers of subgroups classified on the basis of clinical status, indicating that the differences were not likely to be related to differences in clinical status of the patients being tested. Some of this antigenic variation is reflective of known genetic diversity, while some is not. The results suggest that undefined preserved and variable regions containing neutralization epitope(s) exist. These data do not indicate a need to define antigenic subtypes of HIV-1 at present. The existence of conserved neutralization epitope(s) may indicate the potential for broad immunogenicity of appropriately selected vaccine antigens.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID

摘要:

Summary:The virion particles of all retroviruses contain reverse transcriptase, a multifunctional enzyme required for the synthesis of a DNA copy of the viral RNA genome soon after entry into the infected cell. The enzyme is the target of the major antiviral drugs currently in use in the treatment of AIDS. This article reviews the strategies used by different retroviruses for the synthesis of the enzyme; the structure of the enzymes encoded by various viruses; the activities inherent in the enzyme; and the application of those activities to the process of reverse transcription of the viral RNA.

ISSN:0894-9255    

出版商:OVID    

年代:1990

数据来源: OVID