Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Flow cytometric detection of human immunodeficiency virus (HIV)-infected lymphoid cells at low frequencies is described. Infected cells from human T lymphoid cell lines H9 and A3.01 were detected at frequencies as low as 10(-4) following indirect immunofluorescence labeling. For labeling, cells were treated with an HIV-inactivating, permeabilizing fixative followed by binding of a monoclonal antibody specific for the HIV major core protein p24, and then by binding of fluorescein isothiocyanate-conjugated F(ab')2 fragments of goat anti-mouse immunoglobulin antibody. We compared two fixation procedures, one using a mixture of methanol and acetone, the other a three-step fixation using methanol, paraformaldehyde and Triton X-100. The latter fixation protocol was found to be superior in its ability to resolve mixtures of infected and uninfected cells. The method allowed determination of the percentage of the cell population that was infected and the relative amount of p24 antigen per cell. At analysis rates of several thousand cells/s, detection of HIV-infected cells as rare events was possible. Excellent agreement was obtained between flow cytometric evaluation and reverse transcriptase (RT) assay of infected H9 cells cocultured with uninfected H9 cells in various proportions for 7 days. In time course of infection experiments, cultures infected by small numbers of viral particles were positive by flow cytometry up to 3 days earlier than by RT assay.
 ...
PMID:Detection of human immunodeficiency virus-infected lymphoid cells at low frequency by flow cytometry. 244 28

AL-721 is a lipid compound composed of neutral lipids, phosphatidylcholine and phosphatidylethanolamine in a 7:2:1 ratio. The objective of this open study was to evaluate the effects of AL-721 in vivo in an 8-week open trial in which 10 g twice daily was administered on a low fat diet to eight HIV-infected subjects with lymphadenopathy syndrome (LAS). Serial lymphocyte cocultivation studies in 7 patients with initial culture positivity appeared to demonstrate reduction of reverse transcriptase peak counts in 5 with the trough noted in 4 at 8 weeks and in one at 4 weeks following termination of therapy. The mean values for all 7 patients revealed a baseline value of 73,419 with decrease to a low of 27418 at 8 weeks. Mean levels of total lymphocytes, T-4, T-8 and T-11 cells were not altered but lymphoproliferative responses to concanavalin A and pokeweed mitogens appeared to be augmented in 4 of the 8 subjects in association with AL-721 treatment. No side effects were noted. In a subsequent follow-up study using a normal diet in the same subjects lymphocyte cocultivation and mitogen-induced responses were less consistently affected when 15 g twice daily AL-721 was readministered. In addition, serum HIV p24 antigen and CD4 levels were not altered during both the 8-week open and subsequent AL-721 readministration. Four of the 8 patients have progressed to AIDS over the subsequent 14 months.
 ...
PMID:Open study of AL-721 treatment of HIV-infected subjects with generalized lymphadenopathy syndrome: an eight week open trial and follow-up. 245 39

A series of nucleotide homo- and heterodimers [3'-azido-3'-deoxythymidilyl-(5',5')-2',3'-di-deoxy-5' adenylic acid (AZT-P-ddA), 3'-azido-3'-deoxythymidilyl-(5',5')-2', 3'-dideoxy;-5'-adenylic acid, 2-cyanoethyl ester [AZT-P(CyE)-ddA], 3'-azido-3'-deoxythymidilyl-(5',5')-2',3'-dideoxy-5'-inosinic acid (AZT-P-ddI), and 3'-azido-3'-deoxythymidilyl-(5',5')-3'-azido-3'-deoxy-5'-thymid ilic acid (AZT-P-AZT)] were synthesized and compared with respect to their anti-HIV and cytotoxic properties to their component monomers in vitro. MT-2 cells were infected with HIV (TM) followed by the addition of drug. The dimers and their respective monomers inhibited HIV-induced syncytia formation, reverse transcriptase production, and the expression of HIV p24 antigen. However, on an equimolar basis, greater anti-HIV potency and enhanced cytotherapeutic indices were observed with the heterodimers when compared with their monomers. Nucleotide dimers, such as AZT-P-ddA, should be actively considered for further evaluation as anti-HIV agents.
 ...
PMID:Nucleotide dimers suppress HIV expression in vitro. 246 62

The effect of fusidic acid on the multiplication of human immunodeficiency virus in monocyte-derived macrophages was examined in in vitro cultures. Virus titers, measured by reverse transcriptase and by p24 antigen in the supernatants and in lysed cells, were reduced in some experiments by 50 micrograms/ml or more; in other experiments, 10 micrograms of fusidic acid per ml added to the cells simultaneously with the virus inoculation reduced virus titers. The effect was comparable in peripheral blood lymphocytes. The drug was generally toxic to the cells, both macrophages and peripheral blood lymphocytes, in concentrations of 50 micrograms/ml or more.
 ...
PMID:Lack of activity of fusidic acid against human immunodeficiency virus in monocytes. 247 11

Infection with the human immunodeficiency virus (HIV) is often followed by a prolonged latent state, and mechanisms of maintaining latency or inducing expression from latency are active areas in AIDS research. It has been previously shown using a variety of viruses and cell systems that ultraviolet (UV) irradiation is capable of inducing the expression of latent viruses as well as augmenting the effects of acute viral infection. The ability of UV irradiation to affect HIV latency was investigated using a chronically HIV-infected, virus nonexpressing promonocytic cell line termed U1. After exposure to UV-C in doses ranging from 0.75 to 2.0 mJ/cm2, U1 cells were induced to express virus as assessed by detection of elevated reverse transcriptase activity and p24 antigen levels in culture supernatants of treated cells compared with unstimulated controls. In addition, immunofluorescence on cytospin preparations of UV-irradiated cells revealed a time-dependent increase in viral antigen production after UV stimulation. A similar increase in RT levels was seen after exposure of U1 cells to UV-B, although somewhat higher doses of UV-B (mJ) were required compared with UV-C (mJ). Viral induction by UV irradiation was associated with a drop in viability and a static growth curve, suggesting that a certain level of cellular stress was most likely necessary to initiate viral expression. The potential role of UV-induced cell damage with activation of a cellular "SOS" repair response is a probable explanation of the enhanced viral production observed.
 ...
PMID:Induction of expression of human immunodeficiency virus in a chronically infected promonocytic cell line by ultraviolet irradiation. 247 51

Three enzyme immunoassay (EIA) methods for the detection of human immunodeficiency virus (HIV-1) were evaluated. Serum or plasma samples from 22 individuals seropositive for HIV-1 antibodies were tested with the Abbott, Coulter, and DuPont kits for presence of HIV-1 p24 antigen. Another 12 samples were tested with two kits only. Discordant results were obtained with 9 of 34 (26%) HIV-1-antibody-positive patient samples tested. Most of these discrepancies were found in samples containing less than 30 pg/ml of HIV-1 p24 core antigen. A sampling of sera from normal blood donors and patients with infectious or autoimmune diseases revealed a low level of false positive reactions, especially with sera containing antinuclear antibodies or rheumatoid factor. Noteworthy is the frequency of false positive reactions seen with the DuPont EIA for HIV-1 p24 antigen. 18/111 sera (16.2%) containing auto-antibodies tested positively with the DuPont HIV-1 p24 antigen EIA. The nonspecific nature of the test reactivity for 9/10 of these samples was confirmed using an HIV-1 p24 antigen inhibition assay. These findings are discussed in light of the need for HIV-1 antigen detection in the clinical laboratory and of other methods for HIV-1 detection: the polymerase chain reaction and measurements of reverse transcriptase activity.
 ...
PMID:Evaluation of three enzyme immunoassays for HIV-1 antigen detection. 251 47

Bovine leukaemia virus (BLV) and the human T-cell leukaemia/lymphoma viruses I and II represent a specific group of type-C RNA tumour viruses characterized by the presence between the err gene and the 3'LTR of an "x" region or LOR frame, which codes for a protein that trans-activates the transcription of the viral genome. As BLV can also infect sheep and induces pre B-cell specific tumours in these animals, we were interested in investigating whether suramin, a potent inhibitor of retrovirus-associated reverse transcriptase, may inhibit the in vivo multiplication of BLV in sheep. The sheep were infected with 4 X 10(7) leukocytes from a BLV-infected cow. The animals were maedi-visna virus-negative. Viral p24 antigen and reverse transcriptase appeared at 2 weeks and seroconversion occurred at 4 weeks after infection. Suramin was administered at 20 mg/kg/week from the 10th till the 16th week after infection. During the treatment period the expression of p24 antigen as well as the titre of anti-p24 and anti-gp51 antibodies were followed. Suramin treatment led to a significant, but transient, disappearance of p24 antigen and did not affect the titre of anti-p24 and anti-gp51 antibodies. The BLV-infected sheep may serve as a useful animal model for the investigation of retrovirus inhibitors and the evaluation of different therapeutic regimens.
 ...
PMID:Treatment of bovine leukaemia virus-infected sheep with suramin: an animal model for the development of antiretroviral compounds. 257 36

Cell lines originally derived from malignant tumours of the brain were infected by diverse human immunodeficiency virus types 1 and 2 (HIV-1 and HIV-2) isolates. By surface immunofluorescence it was shown that susceptible cells did not bear the CD4 antigen. They were also non-permissive for the formation of plaques by vesicular stomatitis virus pseudotypes and did not form syncytia with HIV-producing cells. Virus production was of low titre, and reverse transcriptase and the p24 antigen were consistently undetectable in the culture supernatants. Output virus could be detected by cocultivation with a sensitive T cell line, C8166, by the culture of supernatant medium with T cells and by detection of proviral HIV DNA after amplification. A higher multiplicity of input virus was required to establish a brain cell infection than was required for T lymphocytes or monocytes. Some HIV-susceptible brain cells contained mRNA for CD4 but infection was not blocked by anti-CD4 antibodies. Apparently HIV infection of these cells does not involve CD4 as the cellular receptor.
 ...
PMID:Infection of brain cells by diverse human immunodeficiency virus isolates: role of CD4 as receptor. 267 35

Since the detection of antibodies against the human immune deficiency virus (HIV) does not definitely prove HIV infection in hemophiliacs, virus detection was attempted by virus isolation from the peripheral blood monocytes (PBL), by demonstration of p24 antigen and decline of p24 antibody, and by detection of viral DNA by the polymerase chain reaction (PCR). Virus isolation was optimized by immediate coculture of PBL and by replacement of the reverse transcriptase test by the p24 antigen test, whereas the elimination of CD8+ lymphocytes proved to be unnecessary. Virus detection was dependent on the clinical stage of the illness. Virus isolation in 70 of 211 patients (33%) was more sensitive than detection of p24 antigen or decline of p24 antibody. PCR was performed in 25 patients and indicated infection in all of 15 isolation-positive cases and in 6 of 10 patients from whom virus was not isolated. Changes from negative to positive virus culture and from a weakly fusiogenic to a highly fusiogenic isolate were often accompanied by a progression of the disease. The results suggest that reactivation of HIV occurs when immune deficiency has become manifest. Apparently virus isolation detects only the virus already reactivated in vivo, whereas the PCR may also detect latent virus.
 ...
PMID:Comparison of different methods for detecting human immune deficiency virus in human immunodeficiency virus-seropositive hemophiliacs. 268 96

The biological response modifier r(I)n.r(C12-U)n, referred to here as mismatched double-stranded (ds) RNA, was examined for antihuman immunodeficiency virus (HIV) activity in vitro because of its known antiviral activity and ability to induce interferon (IFN) in other biological systems [Carter, W. A., Strayer, D. R., Hubbell, H. R. & Brodsky, I. (1985) J. Biol. Response Modif. 4, 495-502]. We found that cultures of the highly HIV-permissive T-cell line C3 were afforded significant protection from HIV infection when incubated in growth media supplemented with mismatched dsRNA at 10-50 micrograms/ml prior to virus challenge. Similar results were obtained at 50 micrograms of mismatched dsRNA per ml in cultures of the T-lymphoblastoid cell line CEM. Infections were monitored by indirect immunofluorescence of cells for viral p24 antigen expression, reverse transcriptase activity in culture fluids for virus production, and vital dye uptake for cytopathic effect. Antiviral activity was increased by the continued presence of mismatched dsRNA in cultures following virus challenge. A one-time exposure to mismatched dsRNA (50 micrograms/ml) provided greater antiviral activity than either a one-time exposure to recombinant IFN-alpha [250 international units (IU)/ml], IFN-beta (250 IU/ml), or IFN-gamma (50 IU/ml) in cultures of CEM cells, or a one-time exposure to a combination of all three IFNs (150 IU each per ml) in cultures of C3 cells. Mismatched dsRNA at 50 micrograms/ml had no effect on cell division, RNA and protein synthesis, or virus replication in all T-cell lines examined. A clear distinction between the activities of mismatched dsRNA and IFN was the ability of IFN to suppress the in vitro replication of HIV that occurred at IFN concentrations (150 IU each of alpha, beta, and gamma per ml) that provided less antiviral activity than mismatched dsRNA (50 micrograms/ml). The results of these in vitro studies suggest a potential therapeutic value for mismatched dsRNA in the treatment of acquired immunodeficiency syndrome (AIDS).
 ...
PMID:Antiviral activity of mismatched double-stranded RNA against human immunodeficiency virus in vitro. 310 82


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>