摘要:

Objective:To analyse the role of recombinant HIV-1 protein p17 in the modulation of cell activity.Methods:Peripheral blood mononuclear cells (PBMC) obtained from healthy donors were cultured in the presence or absence of p17 with mitogens such as phytohaemagglutinin or interleukin-2 and their response assayed by cell proliferation. Cross-linking experiments were employed to investigate the presence of a binding between p17 and factor(s) present in human serum. An immunoenzymatic assay for p24 antigen detection was used to analyse the effect of the addition of exogenous p17 to cultures of PBMC infected with HIV-1in vitro.Results:Purified recombinant p17 protein at a concentration of 0.25 µg/ml significantly increased the proliferation of preactivated PBMC obtained from healthy donors. This effect was obtained by binding p17 to factor(s) present in human serum and observed on both CD4+ and CD8+ T cells. Recombinant p17 also induced an increased rate of HIV-1 replication, probably due to enhanced T-cell proliferation. The activity of p17 protein was inhibited by anti-p17 antibodies generated by injecting recombinant p17 in rabbits, but not by human antibodies generated during the natural course of HIV infection.Conclusion:Characterization of the human factor(s) and identification of the interacting p17 epitope(s) will improve our understanding of the mechanisms used by HIV to efficiently replicate in our organisms.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objectives:To study the role of the hematopoietic transcription factor GATA-2 in long terminal repeat (LTR)-directed transcriptional activation of HIV-1 in hematopoietic progenitor cells, and to investigate possible GATA-2 binding sites in HIV-1 LTR.Design and methods:Wild-type HIV-1 LTR, or mutants, ligated to a luciferase reporter gene with or without a GATA-2 expression vector, were transfected into COS cells, and standardized luciferase activity was examined. The binding activity of GATA-2 to these sites was examined by electrophoretic mobility shift assay. These wild-type or mutant reporter genes were also transfected into the murine hematopoietic progenitor cells, BAF3, in which GATA-2 was the predominantly expressed transcription factor of the GATA family, to assay LTR-directed transcription in intact hematopoietic machinery. Using a Tat expression plasmid for cotransfection, the influence of Tat protein on GATA-2-induced transactivation was determined.Results:In COS cells, LTR-dependent transactivation was highly enhanced by the coexpression of GATA-2. Experiments with mutant LTR suggested the presence of multiple GATA-2 binding sites, of which the major sites were identified. Cotransfection of Tat with GATA-2 indicated that GATA-2 and Tat synergistically enhanced the transcriptional activity. Transfection experiments in BAF3 cells showed that the disruption of these GATA sites diminished LTR-driven activity to 40% of the wild-type.Conclusions:GATA-2 may be a key host cell regulator of HIV-1 expression in hematopoietic stem cells. Manipulating this transactivation may represent a valuable approach to controlling virus production in infected hematopoietic progenitors. To elucidate the possible interaction between GATA-2 and Tat proteinin vivomight give new insights to the mechanism of impaired hematopoiesis in AIDS patients.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective and design:Extracellular Tat released from HIV-1-infected cells is a mitogenic and motogenic factor for endothelial and Kaposi's sarcoma (KS)-derived cells and is angiogenicin vivo. Here we show for the first time that Tat induces migration of human dendritic cells in a concentration-dependent manner and that the Arg-Gly-Asp (RGD) and basic Tat peptides contribute to dendritic and monocyte cell migration.In vivo, Tat stimulates invasion of macrophages into a matrigel sponge.Methods:Monocyte and dendritic cell chemotaxis was assessed using the Boyden chamber assay.Results:Tat induced migration of monocyte-derived dendritic cells at the same levels as theN-formyl-Met-Leu-Phe peptide, and of monocytes at levels comparable to RANTES. Peptide mapping of the chemotactic activity of Tat showed that the RGD domain, which has been shown to support integrin-mediated cell migration, and the basic domain which binds and activates the tyrosine kinase receptor KDR on endothelial cells, both had activity. Antibody-blocking experiments indicate that responses to the RGD domain was inhibited by β1 and αvβ3 integrin blocking antibodies. Combination of the Tat RGD and basic peptides did not show additive effects; however, Tat co-operated with macrophage-chemotactic protein or RANTES in inducing monocyte migration.Conclusions:Our results show that Tat can act as a chemoattractant for dendritic cells, and that both the RGD and basic domains are involved in this response. These same domains attract monocytes. The αvβ3 and β1 integrins are equally involved in Tat-induced monocyte migration, while the αvβ3 integrin largely mediates the dendritic cell response to Tat.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:Evaluate safety and efficacy of oral ganciclovir (GCV) for preventing cytomegalovirus (CMV) disease in HIV-infected persons at high risk for CMV disease.Design:Double-blind, placebo-controlled, randomized clinical trial in primary care clinics and private practice offices specializing in the care of people with HIV. Interventions were oral GCV (1000 mg three times/day) or placebo. Protocol amendment allowed switch to open-label oral GCV. Main outcome measures were confirmed CMV retinal or gastrointestinal mucosal disease, and death. The study enrolled 994 people co-infected with CMV and HIV, with at least one CD4 count recorded < 100 × 106cells/l.Results:At study completion (15 months median follow-up), CMV event rates in the oral GCV and control groups were 13.1 and 14.6 per 100 person years, respectively, a hazard ratio (HR) of 0.92 [95% confidence interval (CI), 0.65–1.27;P= 0.6]. At protocol amendment event rates were 12.7 and 15.0, respectively (HR, 0.85; 95% CI, 0.56–1.30;P= 0.45). At study completion, event rates for death were 26.6 and 32.0 (HR, 0.84;P= 0.09), and at protocol amendment were 18.9 and 19.6 (HR, 0.95;P= 0.78), respectively. At protocol amendment for the CMV endpoint, the oral GCV treatment effect was associated with baseline use of didanosine (ddI). For patients taking ddI at randomization, HR was 7.48 (P= 0.02). For patients not taking ddI, HR was 0.62 (P= 0.04). These HR were statistically different (P= 0.0006).Conclusions:In our study, 3 g/day oral GCV did not significantly reduce CMV disease incidence, but there was a suggestion of a death-rate reduction. Furthermore, results suggest that oral GVC decreased risk of CMV disease in patients not prescribed ddI, and increased risk in those prescribed ddI. For the CMV endpoint, our study differs markedly from the only similar study, although for the death endpoint, a combined analysis of studies indicated significant reduction in death rate.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:To study the antiviral effect and predictors of response to two- and three-drug regimens amongst antiretroviral-naive individuals using an intent-to-treat analysis.Main outcome measure:Suppression of plasma viral load to <500 copies/ml.Patients:A total of 420 (264 double drug, 156 triple drug) individuals in a province-wide treatment programme were studied.Results:A decrease in plasma viral load to < 500 copies/ml was documented in 197 (47%) subjects. This was independently associated with a lower baseline plasma viral load (odds ratio, 3.67; 95% confidence interval, 2.13–6.30) and initiation onto a three-drug regimen (odds ratio, 3.86; 95% confidence interval, 2.24–6.66). Median plasma viral load failed to reach < 500 copies/ml and in fact rebounded in the two-drug group. In contrast, 91 (58%) subjects receiving three drugs reached <500 copies/ml during the study period.Conclusion:These results support the use of powerful triple drug regimens as initial therapy in HIV-infected individuals.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:To investigate the suitability of HIV sequence analysis, based on the p17 region of thegaggene, to characterize the sexual networks in and around a trading town in south-west Uganda.Methods:Blood samples were obtained from 54 HIV-seropositive members of three distinct sexual networks and phylogenetic analysis carried out on proviral DNA sequences obtained from the p17 region ofgagfrom 53 individuals.Results:Despite documented evidence of very little sexual mixing between residents of the trading town, fishing village and surrounding rural area, there was no evidence of clustering of sequences associated with place of residence. More strikingly, known sexual partners failed to show significantly related sequences, and the two pairs of sequences that did show significant similarity came from individuals who had no known social or sexual contact.Conclusions:Sequence analyses such as those described here have proved effective in confirming or identifying epidemiological links not only following single transmission events but also within risk groups. However, the results from Uganda contrast markedly with those from Europe and the United States. The length of time that the community has been infected, the number of occasions when the virus has been introduced and the high degree of partner change may contribute to the lack of supportive evidence for sociological studies of sexual networks in Uganda.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objectives:To determine the genetic variability of HIV-1 amongst infected Filipinos and to analyze phylogenetic relationships, temporal introductions and transmission dynamics of identified variants.Methods:Polymerase chain reaction amplification and direct sequencing of a 204 base-pair fragment of theenvC2–V3 region from uncultured peripheral blood mononuclear cells obtained from 51 HIV-1-positive Filipinos infected from 1987 to mid-1996. Evolutionary distance and phylogenetic relationships among the DNA sequences were estimated.Results:The 51 Philippine strains were classified into fiveenvV3 subtypes, namely subtype B (n = 37), subtype E (n = 8), subtype A (n = 3), subtype C (n = 2) and subtype D (n = 1). The overallenvnucleotide divergence ranged from 11.7 to 32.2%. The nucleotide variation appeared to be random and no temporal ordering was observed. The variation of the sequences at the tip of the V3 loop was very broad. Subtypes B and C isolates did not show close genetic relationship to other Asian variants. Only three of the subtype E strains had close affinity to known Asian sequences. The majority (94%) of the subjects acquired the infection by sexual transmission. About two-thirds were presumably infected outside the Philippines, whereas the remaining were infected indigenously. Information was limited to allow segregation of the identified subtypes by mode of transmission or risk groups.Conclusion:Our findings demonstrate the presence of multiple genetic subtypes of HIV-1 in the Philippines. The apparent geographic range of previously reported genotypes in South and South-east Asia was extended and has obvious implications forenv-based antiviral interventions.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objectives:To evaluate the impact of perinatal zidovudine use on the risk of perinatal transmission of HIV and to determine risk factors for transmission among women using perinatal zidovudine.Design:Prospective cohort study of 1533 children born to HIV-infected women between 1985 and 1995 in four US cities.Methods:The association of potential risk factors with perinatal HIV transmission was assessed with univariate and multivariate statistics.Results:The overall transmission risk was 18% [95% confidence interval (CI), 16–21]. Factors associated with transmission included membrane rupture > 4 h before delivery [relative risk (RR), 2.1; 95% CI, 1.6–2.7], gestational age < 37 weeks (RR, 1.8; 95% CI, 1.4–2.2), maternal CD4+ lymphocyte count < 500 × 106cells/l (RR, 1.7; 95% CI, 1.3–2.2), birthweight < 2500 g (RR, 1.7; 95% CI, 1.3–2.1), and antenatal and neonatal zidovudine use (RR, 0.6; 95% CI, 0.4–0.9). For infants exposed to zidovudine antenatally and neonatally, the transmission risk was 13% overall but was significantly lower following shorter duration of membrane rupture (7%) and term delivery (9%). The transmission risk declined from 22% before 1992 to 11% in 1995 (P< 0.001) in association with increasing zidovudine use and changes in other risk factors.Conclusions:Perinatal HIV transmission risk has declined with increasing perinatal zidovudine use and changes in other factors. Further reduction in transmission for women taking zidovudine may be possible by reducing the incidence of other potentially modifiable risk factors, such as long duration of membrane rupture and prematurity.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:To study the spectrum of neuropathological brain lesions in HIV/AIDS cases.Design:Retrospective autopsy study between 1988 and mid-1996 at a tertiary level public hospital.Methods:Eighty-five adult brains, with at least 21 sections from each, were examined using routine and special stains.Results:Risk factors in 64 men (75%) and 21 women (25%) included heterosexual contact with multiple sexual partners (83 cases, 98%), homosexual behaviour (one case, 1%) and blood transfusion (one case, 1%). Central nervous system (CNS) lesions were observed in 67 cases (79%). Opportunistic infections were present in 33 cases (39%), which included toxoplasmosis (11 cases, 13%), tuberculosis (10 cases, 12%), cryptococcosis (seven cases, 8%), and cytomegalovirus infection (six cases, 7%). Multifocal myelin loss was observed in 18 cases (21%), microglial nodules in 15 cases (18%), and angiocentric pallor in five cases (6%). Infarcts/haemorrhages were present in 13 cases (15%), choroid plexitis in 21 cases (25%), lymphocytic meningitis without opportunistic infection in 21 cases (25%), and calcification in four cases (5%). A dual infectious pathology was observed in one case (1%). Multinucleated giant cells and primary CNS lymphoma were not found in any of our cases.Conclusions:Patient profile and risk factors for AIDS in India differ from those reported in industrialized countries. Although not reported from India in the pre-AIDS era, toxoplasmosis was the most frequently observed CNS opportunistic infection in our study. CNS tuberculosis is frequently observed in Indian AIDS cases compared with reports from industrialized countries where its occurrence is uncommon. Death due to systemic opportunistic infections may punctuate the course of HIV encephalitis and prevent its full-blown morphological expression.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID

摘要:

Objective:To estimate the age and sex-specific prevalence of HIV infection in the population of Addis Ababa, Ethiopia.Design:Two-stage cluster sampling of the population aged 0–49 years of Addis Ababa, using kebeles (urban dwelling associations) as clusters.Methods:The sera used for this study were collected in an earlier study (1994) on the rate of acquisition of antibodies against measles, rubella, and hepatitis B. After separate approvals were obtained from the institutional ethics committees, sera were tested by enzyme-linked immunosorbent assay confirmed by Western blot. Age- and sex-specific HIV prevalence rates were estimated. The prevalence of HIV in men and women over 15 years of age was compared by calculating age-standardized HIV prevalence, using the age distribution of the census population as the standard. A time-dependent catalytic model was used to obtain crude estimates of HIV incidence from age-prevalence data.Results:A total of 3853 sera were available for analysis. The prevalence of HIV in adults was 6.0% [95% confidence interval (CI), 4.5–7.4%] for men and 6.9% (95% CI, 5.3–8.5%) for women, with peak prevalence in the 25–29 year age group of 16.3 and 11.8%, respectively. After standardization for age using the direct method, the HIV prevalence ratio comparing adult men with women was 0.97: 1 (95% CI, 0.70: 1 – 1.35: 1). Three children aged less than 5 years were HIV-positive. The prevalence of HIV among adults ranged from 0–21.3% in different clusters, indicating the heterogeneity of the spread of HIV in the city. HIV prevalence estimates among the antenatal clinic patients of Addis Ababa in 1996 far exceeded the estimates obtained during the community survey, particularly in the youngest age group (15–24 years). Estimates of HIV incidence (per susceptible person per annum) for the age group 16–22 years ranged from 1.3–2.25% for men and from 2.1–2.4% for women.Conclusion:By 1994, a substantial proportion of the adult population of Addis Ababa was infected with HIV. Promotion of behavioural changes and the control of sexually transmitted diseases should be strongly supported to limit the spread of the HIV epidemic in Ethiopia.

ISSN:0269-9370    

出版商:OVID    

年代:1998

数据来源: OVID