摘要:

ObjectiveThis study examines the effects of the HIV-1 regulatory proteins, Tat and Rev, on the expression of the DNA polymerase β (β-pol) gene, which encodes a key protein in the DNA base-excision repair pathway. The rationale for these experiments is to examine the potential involvement of base-excision repair protein deregulation in HIV-1-related lymphomas.DesignExpression of β-pol mRNA was examined in AIDS-related lymphomas and non-AIDS-related lymphomas and as a function of HIV-1 infection of B cells in culture. The effect of Tat or Rev over-expression on β-pol promoter expression was tested by transient co-transfection assays with a β-pol promoter reporter plasmid and a Tat or Rev over-expression plasmid.MethodsNorthern blot analysis was used to quantitate β-pol expression in lymphoma and cells. Raji cells were co-transfected with a chloramphenicol acetyltransferase (CAT) reporter plasmid and a plasmid over-expressing Tat or Rev. CAT activity was measured in transfected cells.Resultsβ-Pol mRNA was > 10-fold higher in AIDS-related than in non-AIDS B-lineage lymphomas. β-Pol expression was up-regulated in a B-cell line upon infection with HIV-1, and increased in Raji cells upon recombinant expression of the Tat gene. The β-pol promoter was transactivated (fourfold induction) by Tat, but not by Rev. Tat-dependent transactivation required a binding site for the transcription factor Sp1 in the β-pol promoter.ConclusionThese results suggest that HIV-1 Tat can interact with cellular transcription factors to increase the steady-state level of β-pol in B cells. Tat-mediated induction of β-pol may alter DNA stability in AIDS-related lymphomas.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectivesTo identify a substance found in female genital tract secretions that enhances HIV expression in infected cells.DesignCervico-vaginal lavages (CVL), collected in sterile normal saline, were fractionated and tested for HIV-inducing activity using HIV-infected monocytes.MethodsTo purify the component(s) of CVL that enhance HIV production, Mono-Q ion exchange chromatography followed by Superose-12 molecular sieve analysis, and SDS–PAGE were performed. The purified protein was identified by amino acid sequence analysis.ResultsSDS–PAGE of bioactive fractions showed a 14 kDa polypeptide band. Amino acid sequence analysis of selected peptides from the 14 kDa band showed 100% homology with the myeloid-related protein (MRP)-8, an inflammatory protein found in mucosal secretions. Western blot analysis revealed that bioactive CVL contained more immunoreactive MRP-8 than samples without bioactivity. The HIV-inducing activity of MRP-8 was further confirmed by showing that human recombinant MRP-8 increased HIV expression by up to 40-fold.ConclusionsMRP-8 in cervico-vaginal secretions stimulates HIV production. Strategies aimed at blocking MRP-8 activity in the genital tract could reduce risk of sexual as well as maternal–infant transmission of HIV.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectivesTo analyse the importance of sequence variations in the internal transcribed spacer (ITS) regions 1 and 2 of the nuclear rRNA operon in AIDS patients withPneumocystis cariniipneumonia (PCP).Design and methodsITS 1 and 2 genotypes were determined in 162 bronchoalveolar lavage samples from 130 patients participating in a prospective cohort study of PCP.ResultsA total of 49 different ITS genotypes were detected. ITS genotype was not associated with the clinical severity or outcome of PCP. In 37 of 162 (23%) samples infection with two or more genotypes was observed. A genotype switch was detected in six of 10 patients (60%) with recurrent episodes of PCP. However, genotype changes were also seen in 10 of 19 patients (53%) who had repeated bronchoscopies within the same episode of PCP. The same ITS type was observed twice in 13 (46%) of the 28 patients with repeat bronchoscopies during single or recurrent episodes of pneumonia, but in only 14 of 81 (17%) randomly selected pairs (P< 0.01).ConclusionAlthough the detection of ITS genotypes is not a random event, changes in genotype can be detected in a single episode of disease, with 23% of PCP patients being infected with more than oneP. cariniigenotype, thus complicating the use of this locus as a genetic marker to separate new infection from the reactivation of latent infection. ITS genotypes are not associated with the clinical severity of PCP.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo describe the epidemiology of severePneumocystis cariniipneumonia (PCP) in HIV-infected and non HIV-infected patients.MethodsBronchoalveolar lavage specimens from 212 European patients with PCP were typed using PCR–single strand conformation polymorphism analysis of four genomic regions ofP. cariniif. sp.hominis. Demographic and clinical information was obtained from all patients.ResultsTwenty-three per cent of the patients were presumably infected with a singleP. c. hoministype. The other patients presented with two (50%) or more (27%) types. Thirty-five genetically stable and ubiquitousP. c. hoministypes were found. Their frequency ranged from 0.4% to 10% of all isolates, and up to 15% of those from a given hospital. There was no significant association between theP. c. hoministype or number of co-infecting types per patient and geographical location, year of collection, sex, age, or HIV status. No more than three patients infected with the same type were observed in the same hospital within the same 6 month period, and no epidemiological link between the cases was found.ConclusionsThe broad diversity of types observed seems to indicate that multiple sources of the pathogen co-exist. There was no evidence that in our study population inter-human transmission played a significant role in the epidemiology ofP. carinii.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundPleural tuberculosis can resolve spontaneously, suggesting that the inflammatory process may represent a protective immune response. However, pleural tuberculosis is strongly associated with HIV infection. It has been suggested that cell-mediated immune responses may be reduced, and direct bacterial invasion may have a role in pathogenesis, in HIV-positive cases. To test this hypothesis, we compared production of the pro-inflammatory cytokines, interferon (IFN)-γ and tumour necrosis factor(TNF)-α, production of the immunosuppressive cytokine, interleukin (IL)-10, and mycobacterial culture positivity, in HIV-negative and HIV-positive patients with pleural tuberculosis.MethodsCytokine levels were measured in serum and pleural fluid, and in supernatants of blood and pleural fluid stimulatedin vitrousing mycobacterial antigens. Intracellular IFN-γ and TNF-α production was measured after stimulation with phorbol myristate acetate and ionomycinin vitro.ResultsIFN-γ was strikingly elevated in serum and pleural fluid in HIV-positive, compared to HIV-negative subjects (P⩽ 0.02). TNF-α was elevated, but this was not statistically significant. IL-10 levels were higher in serum (P< 0.001), but similar in pleural fluid. IFN-γ responses to soluble mycobacterial antigenin vitrowere reduced in peripheral blood (P= 0.006), but not pleural fluid, of HIV-positive subjects. Intracellular cytokine staining suggested that CD8+ T cells were a major source of IFN-γ in HIV-positive subjects. The proportion of subjects with a positive culture forMycobacterium tuberculosisfrom pleural fluid was higher in the HIV-positive group.ConclusionsHIV-positive patients with pleural tuberculosis show elevated production of IFN-γ, for which CD8+ T cells may be a major source.Mycobacterium tuberculosiscan proliferate despite high levels of pro-inflammatory cytokines.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo examine if peripheral T lymphocytes from HIV-infected individuals show abnormalities in the surface expression of CD43, the major sialoglycoprotein of leukocytes.DesignA series of 86 HIV-positive individuals was studied. The subjects, grouped by their peripheral CD4 cell count, were in different stages of the disease as defined by the Centers for Disease Control and Prevention (CDC).MethodsPeripheral leukocytes and isolated lymphocytes were examined by double and triple immunofluorescence flow cytometric and Western blot analyses with monoclonal antibodies, which discriminate between CD43 isoforms.ResultsWe found elevated percentages of the surface expression of CD43-hexasaccharide isoform on T lymphocytes from 82 out of 86 individuals tested. Increasing percentages are progressively found in CDC groups 1, 2 and 3 patients. The expression of the molecule is remarkably biased towards the CD8 cell subpopulation. The percentage of cells bearing human leukocyte antigen-DR locus molecules (HLA-DR) is also augmented. Two subsets expressing T305 have been identified: a minor subset that co-expresses HLA-DR and T305; and a second population formed by the majority of T305-positive cells, which lack surface HLA-DR. Finally, we found CD43 bands with altered electrophoretic mobility in lysates from peripheral lymphocytes from all HIV-positive individuals tested.ConclusionThe augmented expression of CD43-hexasaccharides and the observed cellular distribution suggest an important regulatory role for this molecule in HIV-specific responses.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveTo investigate the involvement of P-glycoprotein (Pgp) and the multidrug resistance-associated protein (MRP) on the active transport of the HIV protease inhibitors amprenavir, ritonavir and indinavir.MethodsThe transport behaviour of ritonavir, indinavir and amprenavir in the presence and absence of Pgp modulators and probenecid was investigated in anin vitroblood–brain barrier (BBB) co-culture model and in monolayers of LLC-PK1, LLC-PK1:MDR1, LLC-PK1:MRP1 and Caco-2 cells.ResultsAll three HIV protease inhibitors showed polarized transport in the BBB model, LLC-PK1:MDR1 and Caco-2 cell line. The Pgp modulators SDZ-PSC 833, verapamil and LY 335979 inhibited polarized transport, although their potency was dependent on both the cell model and the HIV protease inhibitor used. Ritonavir and indinavir also showed polarized transport in the LLC-PK1 and LLC-PK1:MRP1 cell line, which could be inhibited by probenecid. HIV protease inhibitors were not able to inhibit competitively polarized transport of other HIV protease inhibitors in the LLC-PK1:MDR1 cell line.ConclusionsAmprenavir, ritonavir and indinavir are mainly actively transported by Pgp, while MRP also plays a role in the transport of ritonavir and indinavir. This indicates that inhibition of Pgp could be useful therapeutically to increase HIV protease inhibitor concentrations in the brain and in other tissues and cells expressing Pgp. The HIV protease inhibitors were not able to inhibit Pgp-mediated efflux when given simultaneously, suggesting that simultaneous administration of these drugs will not increase the concentration of antiretroviral drugs in the brain.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectiveSince psychomotor slowing predicts the development of HIV-1-associated dementia, AIDS and death independently of the immune status, there is urgent need for a neurological therapeutic rationale.MethodsThe therapeutic efficacy of nucleoside analogues with different abilities to penetrate into the cerebrospinal fluid was assessed in 410 HIV-1-seropositive patients using the results of detailed fine motor tests, which detect minor motor deficits. Patients were selected who showed pathological psychomotor slowing as signs of central nervous system (CNS) dysfunction before therapy onset and who were then treated only with nucleoside analogues for at least 6 months.ResultsBoth zidovudine and didanosine improve CNS function to an equal degree when given as monotherapy. Adding a second nucleoside analogue (didanosine, lamivudine, zalcitabine) to zidovudine does not further improve psychomotor performance. However, adding a second nucleoside after a period of zidovudine monotherapy does result in a second but less remarkable therapeutic effect. Combinations containing stavudine are as effective as those including zidovudine when given as first antiretroviral treatment. Furthermore, stavudine effectively improves motor performance even after pretreatment with zidovudine.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

ObjectivesTo assess the safety of discontinuation of primary prophylaxis in HIV-infected patients on antiretroviral combination therapy at high risk of developingPneumocystis cariniipneumonia.DesignProspective multicentre study.Patients and methodsThe incidence ofP. cariniipneumonia after discontinuation of primary prophylaxis was studied in 396 HIV-infected patients on antiretroviral combination therapy who experienced an increase in their CD4 cell count to at least 200 × 106/l and 14% of total lymphocytes; the study population included 191 patients with a history of CD4 cell counts below 100 × 106/l (245 person-years) and 144 patients with plasma HIV RNA above 200 copies/ml (215 person-years).ResultsThere was one case ofPneumocystispneumonia, an incidence of 0.18 per 100 person-years [95% confidence interval (CI), 0.005–1.0 per 100 person-years]. No case was diagnosed in groups with low nadir CD4 cell counts (95% CI, 0–1.2 per 100 person-years) or detectable plasma HIV RNA (95% CI, 0–1.4 per 100 person-years).ConclusionsDiscontinuation of primary prophylaxis againstPneumocystispneumonia is safe in patients who have responded with a sustained increase in their CD4 cell count to antiretroviral combination therapy, irrespective of the CD4 cell count nadir and the viral load at the time of stopping prophylaxis.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID

摘要:

BackgroundThe HIV-1 epidemics in Western Europe are dominated by B subtype viruses. Non-B subtype is largely restricted to individuals infected outside of Europe and to their direct contacts and is generally acquired by the heterosexual route.MethodsProtease and a segment of reverse transcriptase were amplified and sequenced from plasma RNA in 451 individuals from seven cities of Galicia, north-western Spain. Subtype sequence homologies were determined using the BLAST algorithm. Non-B sequences were examined by phylogenetic analysis and intersubtype recombination by bootscanning. TheenvV3 region was analysed in all non-B and in 38 B subtype viruses.ResultsTen different non-B genetic forms were identified in 20 (4.4%) individuals. Subtypes were concordant betweenpoland V3 in five viruses; 14 (70%) infections were with intersubtype recombinant viruses, and one individual had a dual B+G infection. Seven recombinant viruses were phylogenetically related to five reported recombinant forms. Three non-recombinant G and six recombinant BG viruses formed a monophyletic cluster forpol. All but three individuals with non-B infections were native Spanish. Only 6 of 16 individuals referred to sexual contacts with sub-Saharan Africans. Twelve (60%) non-B subtype infections, including all with G and BG viruses, were in injecting drug users (IDU).ConclusionsNon-B subtype viruses were identified in 4.4%, with a high diversity of genetic forms, including 70% infections with intersubtype recombinant viruses. The majority of individuals with non-B infections were IDU, most of them without known contacts with non-European sources, and among whom BG recombinant viruses are circulating.

ISSN:0269-9370    

出版商:OVID    

年代:2001

数据来源: OVID