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Query: UMLS:C0019693 (HIV)
 170,526 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The in vitro amplification of biologically important nucleic acids has proceeded principally by a strategy of DNA replication. Polymerase chain reaction was the first such protocol to achieve this goal. In this report, a transcription-based amplification system (TAS) is described. Each cycle of the TAS is composed of two steps. The first is a cDNA synthesis step that produces one copy of a double-stranded DNA template for each copy of RNA or DNA target nucleic acid. During the course of this cDNA synthesis step, a sequence recognized by a DNA-dependent RNA polymerase is inserted into the cDNA copy of the target sequence to be amplified. The second step is the amplification of the target sequence by the transcription of the cDNA template into multiple copies of RNA. This procedure has been applied to the detection of human immunodeficiency virus type 1 (HIV-1)-infected cells. After four cycles of TAS, the amplification of the vif region of the HIV-1 RNA genome was measured to be, on the average, 38- to 47-fold per cycle, resulting in a 2-5 x 10(6)-fold increase in the copy number of the original target sequence. This amplification by the TAS protocol allows the detection of fewer than one HIV-1-infected CEM cell in a population of 10(6) uninfected CEM cells. Detection of the TAS-generated RNA from HIV-1-infected cells can easily be accomplished by means of a bead-based sandwich hybridization protocol, which provides additional specificity for the identification of the amplified HIV-1-specific sequence.
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PMID:Transcription-based amplification system and detection of amplified human immunodeficiency virus type 1 with a bead-based sandwich hybridization format. 291 66

Four asymptomatic homosexual men reverted from positive to negative serologic results for the human immunodeficiency virus, type 1 (HIV-1) over 2.5 years, as shown by enzyme-linked immunosorbent assay (ELISA) and Western blot. Antibody bands in the Western blot from three men were undetectable 6 to 12 months after being positive; gradual fading of the number and intensity of bands was seen in the other man. No HIV-1-p24 antigenemia was detected; cryopreserved peripheral blood mononuclear cells were negative for HIV-1 by standard culture assay. Polymerase chain reaction (gene amplification) assays were done on peripheral blood mononuclear cells and showed the HIV-1 provirus in all subjects 6 to 18 months after the last positive antibody test. Serum specimens from each participant were genetically identical. Polymerase chain reaction showed that peripheral blood mononuclear cells from one subject at different times matched by HLA DNA typing. Clinical and laboratory features of these four men were similar to those of other seronegative subjects. Rare, asymptomatic persons seropositive for HIV-1 may not remain seropositive, but may remain latently infected with HIV-1.
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PMID:Loss of human immunodeficiency virus type 1 (HIV-1) antibodies with evidence of viral infection in asymptomatic homosexual men. A report from the Multicenter AIDS Cohort Study. 271 34

S-2720 and other members of the quinoline/quinoxaline class of HIV-1-specific nonnucleoside reverse transcriptase inhibitors (NNRTIs) select for a glycine to glutamate substitution at residue 190 (Gly 190 Glu) of the reverse transcriptase (RT), when drug-resistant viruses are generated in cell culture. This mutation has not been described to appear upon selection for resistant viral variants using derivatives of any other class of NNRTIs. Notably, the RNA-dependent DNA polymerase activity of the Gly 190 Glu mutant enzyme is drastically diminished with respect to the wild-type RT. We describe here the effects of other amino acid substitutions at position 190 of the RT that were introduced by using site-directed mutagenesis. Polymerase activities and sensitivities to inhibition by a number of NNRTIs were determined for the different RT mutants. In general, an inverse correlation was found between the enzymatic activity and increasing length of the side chain, whereas the size of the residue and the level of resistance to NNRTIs appeared to be positively related. Double mutants, which contain the Gly 190 Glu mutation together with substitutions that confer resistance to other RT inhibitors, were all shown to possess severely diminished polymerase activity.
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PMID:Mutational analysis of residue 190 of human immunodeficiency virus type 1 reverse transcriptase. 751 21

A cohort of human immunodeficiency virus (HIV)-discordant couples was established to evaluate risk factors associated with heterosexual viral transmission. Polymerase chain reaction (PCR) was utilized to document the HIV-uninfected status among members of discordant heterosexual couples and to rule out immunosilent infection. HIV DNA PCR specific for a gag gene region was performed on peripheral blood mononuclear cell samples from 203 HIV antibody-negative adults who have long-term heterosexual relationships with HIV-infected partners. The results were negative for 200 but consistently positive in three individuals. More extensive evaluation of these three individuals with an additional primer pair specific for the envelope gene, quantitative DNA PCR, multiple additional time points, and variable nucleotide tandem repeat analyses revealed specimen processing problems in two cases but an apparent true positive PCR assay in the third case. This subject remains antibody and PCR negative for a 32-month follow-up period. These results confirm previous studies that document a negligible incidence of occult HIV infection as delineated by PCR in antibody negative heterosexual partners of HIV-infected individuals. Specimen processing errors occur at a low rate (1% in this study) and require careful evaluation. The possibility of transient, aborted infection versus successful infection with a long immunosilent period was observed in a single individual. Definitive resolution of infection status will require long-term evaluation.
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PMID:PCR analysis of HIV-seronegative, heterosexual partners of HIV-infected individuals. 758 39

The purpose of this study was to assess the sensitivity and specificity of the polymerase chain reaction (PCR) on induced sputum (IS) for the diagnosis of Pneumocystis carinii pneumonia (PCP) in HIV-infected patients, as well as its diagnostic value and cost as a routine clinical tool. Forty-nine patients with suspected PCP who had IS were studied and if negative, followed by bronchoalveolar lavage (BAL). Pneumocystis carinii was detected in these samples using standard staining techniques. Polymerase chain reaction was used with IS samples in a blinded fashion. The patients with negative BAL samples were closely monitored for 1 month. In the absence of any clinical or radiologic features of PCP during this period, they were considered as being free of PCP. The cost analysis considered only the direct costs of the various tests in three diagnostic strategies: routine BAL (BAL); IS with standard staining, if negative, followed by BAL (IS); and IS with standard staining followed, if negative, by PCR on IS samples (PCR-IS). Using standard staining P carinii was found in 13 cases (6 IS and 7 BAL). None of the 36 patients with negative BAL developed further signs of PCP. Thus, the prevalence of PCP was 26.5% and the sensitivity and specificity of BAL were 100%. Standard staining of IS had a specificity of 100% and a sensitivity of 46.5%. The sensitivity and specificity of PCR-IS were each 100%. The costs of strategies BAL, IS, and PCR-IS were $14,010, $18,300, and $18,040, respectively. The costs of the BAL strategy depended only on the cost of the relevant tests, whereas the costs of strategies IS and PCR-IS depended on the costs of the tests, the sensitivity of IS with standard staining, and the prevalence of PCP in the test population. The routine clinical use of PCR-IS is currently limited by the time required to obtain the results.
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PMID:Use of the polymerase chain reaction technique on induced-sputum samples for the diagnosis of Pneumocystis carinii pneumonia in HIV-infected patients. A clinical and cost-analysis study. 761 Nov 87

Epidermal Langerhans' cells (LC) from human immunodeficiency virus type-1 (HIV-1)-infected patients harbour HIV-1 proviral DNA and RNA. In the present study, we investigated whether LC from epidermis of normal, HIV-seronegative subjects could be infected in vitro with HIV-1. Epidermal cells (EC) spontaneously detached from epidermal sheet cultures were enriched for LC (10-25% of CD1a+/CD4+ cells), deprived of contaminating T cells and then incubated with HIV-1IIIB. After 24 hr, purified LC and LC-depleted EC fractions were obtained by immunomagnetic separation. Polymerase chain reaction (PCR) analysis showed the presence of HIV-1 proviral DNA (gag) only in purified LC. In addition, LC-enriched EC, purified LC, LC-depleted EC or the non-permissive cell line, TF-1, the latter having being previously challenged with HIV-1IIIB for the same length of time as the EC, were co-cultivated with C8166 cells, and the co-cultures assessed for the presence of HIV DNA by PCR. Co-cultures of C8166 cells with purified LC or LC-enriched EC previously exposed to HIV-1IIIB exhibited a time-dependent increase in HIV proviral DNA. In contrast, PCR analysis of C8166 cells co-cultured with either LC-depleted EC or TF-1 cells gave negative results. Finally, C8166 cells co-cultured with HIV-infected LC formed syncytia, showed membrane budding and released numerous retroviral particles. The results indicate that LC from normal subjects can be infected in vitro with HIV and can transmit infection to myeloid cells. This in vitro model may help in understanding the regulation of HIV infection of LC.
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PMID:In vitro infection of human epidermal Langerhans' cells with HIV-1. 763 27

The data on observations, lasting over the period of 6 months, on cotton rats given large doses of highly replicating strain HIV-1zmb by retrobulbar and intraperitoneal injections are presented. The study revealed that in all animals subjected to intraperitoneal infection lymphoid tissue contained integrated areas of protovirus DNA of HIV-1 three months later and cerebral tissue, five months later. Six months after retrobulbar infection the specimens of lymphoid tissue contained protovirus DNA in 100% of cases and the specimens of cerebral tissue, in 80% of cases. Clinical and morphological investigations established the presence of the inflammatory process, though no signs of HIV replication in the body of animals were detected. Polymerase chain reaction is proposed as criterion for the evaluation of HIV infection in animals.
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PMID:[The use of the polymerase chain reaction in modelling HIV infection in animals]. 766 Jul 10

Recent studies suggest human immunodeficiency virus (HIV) may be the cause of HIV-associated idiopathic esophageal ulcer (IEU). However, other causes of esophageal disease in HIV-infected patients have not been evaluated for appropriate comparison. Over a 14-month period 13 patients with IEU as determined by clinical, endoscopic, and pathologic criteria were identified. During the same period nine HIV-infected patients with cytomegalovirus (CMV) esophagitis and one HIV-infected patient each with herpes simplex virus esophagitis and gastroesophageal reflux disease (GERD) were also identified. Polymerase chain reaction (PCR) and in situ DNA hybridization (ISH) were performed on paraffin-embedded tissue formed on paraffin-embedded tissue of endoscopic biopsies of ulcer tissue using standard techniques. Eleven of 13 IEU patients (85%) as compared to seven of nine patients (78%) with CMV had HIV detected by PCR (P = 0.38). HIV was also detected in ulcer tissue from biopsy material from the patient with GERD but not herpes simplex virus esophagitis. In PCR-positive patients, ISH confirmed the presence of HIV in four patients (57%) with CMV and eight (73%) with IEU (p = 0.31). HIV was found only in inflammatory cells and not squamous epithelial cells. Given the similar prevalence of detection of HIV by PCR and ISH in ulcer tissue from both groups of HIV-infected patients as well as the location in rare inflammatory cells, we conclude that HIV infection of squamous mucosa does not appear to be the primary cause of IEU.
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PMID:Evaluation of idiopathic esophageal ulceration for human immunodeficiency virus. 767 79

Progressive multifocal leukoencephalopathy (PML) is a lytic infection of oligodendrocytes by the human papovavirus JC. Patients with defects in cell-mediated immunity are at risk for active disease: a usually lethal demyelination of the brain. PML develops in at least 4% of patients with the acquired immunodeficiency syndrome (AIDS). Definitive diagnosis currently requires brain biopsy. Previous attempts to detect JC virus DNA by polymerase chain reaction in cerebrospinal fluid of PML patients, particularly those with human immunodeficiency virus type 1 (HIV-1) infection, have been of low sensitivity. In the present study, cerebrospinal fluid was assayed by polymerase chain reaction from 26 HIV-1-positive patients with PML, 114 HIV-1-positive control subjects, and 16 control subjects who were HIV-1 negative or were without risk factors for HIV disease. Polymerase chain reaction conditions were optimized to detect a single copy of viral DNA in 50 microliters of cerebrospinal fluid. Specificity of the polymerase chain reaction product was confirmed by size on gel electrophoresis and Southern blot hybridization. JC virus DNA was detected in 24 of 26 samples from patients with PML: 8 of 8 with tissue diagnosis and 16 of 18 with strong clinical and magnetic resonance imaging evidence of PML. Among control subjects, 11 of 130 samples were positive for JC virus: 10 of 114 samples from HIV-infected patients and one from an HIV-negative patient with risk factors for PML and an unexplained hemiparesis. Overall sensitivity was 92% (24/26); specificity was, at minimum, 92% (119/130). Treatments for PML are now in clinical trials.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:JC virus DNA in cerebrospinal fluid of human immunodeficiency virus-infected patients: predictive value for progressive multifocal leukoencephalopathy. 769 39

We examined the ability of human immunodeficiency virus (HIV) type 1 (HIV-1) to infect in vitro, primary brain-derived human microvascular endothelial cells (HMEC) that constitute the blood-brain barrier (BBB). Immunofluorescence (IFA) and antigen capture assays failed to demonstrate p24 antigen from HIV inoculated endothelial cells and supernatants did not contain detectable levels of reverse transcriptase (RT). HIV could be rescued by cocultivation of infected HMEC with a susceptible T-lymphocyte line (CEM-SS), which were then shown to form syncytia and produce RT activity and p24 Ag (IFA, antigen captive assay). Polymerase chain reaction (PCR) was successfully used to amplify HIV-specific gag and env gene sequences from HMEC. CD4 expression was not identified on these cells by IFA. These results suggest that HIV infection of BBB endothelium occurs, but that viral replication is minimal. Infection of the BBB by HIV may give the virus a foothold in the CNS and suggests that the brain might be infected directly and may not be limited to just the passage of infected mononuclear cells.
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PMID:HIV-1 infection of human brain-derived microvascular endothelial cells in vitro. 769 39


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