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

We have made 47 mutations that span the length of the human T-cell leukemia virus type I (HTLV-I) Tax open reading frame. Of the 47 mutations, 38 were substitutions of single amino acids, 5 were missense changes in two or more amino acids, and 4 were deletions. A subset of these mutations includes individual changes of all 26 naturally occurring serines to alanines. By assaying each mutant protein separately on the HTLV-I long terminal repeat (LTR) and the human immunodeficiency virus type 1 (HIV-1) LTR in parallel, we were able to identify regions of Tax selectively necessary for each promoter. A small region in the carboxyl terminus, amino acids 315 to 325, was found to be selectively important for activation of the HTLV-I LTR. Three changes at serine 113, serine 160, and serine 258 were found to specifically affect function on the HIV-1 LTR. Surprisingly, we found that the great preponderance of missense changes (32 of 42) in Tax did not affect function.
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PMID:Mutational analysis of human T-cell leukemia virus type I Tax: regions necessary for function determined with 47 mutant proteins. 143 11

Primate and non-primate species have been used to study the pathobiology of the simian immunodeficiency virus (SIV) and of the human immunodeficiency virus type 1 (HIV-1), respectively, and to develop new therapeutic regimes. Transgenic mice which express either the entire HIV-1 provirus or subgenomic fragments have been used to analyze viral gene products in vivo and may serve as models for the development of agents targeted to select viral functions. Chimeric mice which were created by transplanting human hematolymphoid cells into mice suffering from congenital severe combined immunodeficiency (scid/scid or so called SCID mice), can be infected with HIV-1 and allow one to study the entire HIV-1 replicative cycle. Type C murine leukemia virus models have been used to develop new prophylactic and therapeutic strategies but their use is restricted to the evaluation of select antiviral drug inhibition, targeted to retroviral genes common to both Lentivirinae and Oncovirinae. The role of various animal model systems in the development of anti-HIV-1 and anti-AIDS therapies is summarized.
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PMID:Animal models for anti-AIDS therapy. 144 26

This article reviews the virological and epidemiological data available on transmission of the human immunodeficiency virus type 1 (HIV-1) by breast milk. Colostrum and breast milk are considered major modes of transmission for many animal retroviruses as well as human T-cell leukemia virus, mainly as the consequence of ingestion of infected cells. Several cases that strongly suggest transmission of HIV-1 through breast-feeding have now been reported. In addition, recent evidence suggests that postpartum HIV-1 seroconversion of a mother may be associated with a high risk of postnatal transmission to offspring via breast milk. Preventive measures such as pasteurization of breast milk have not been fully examined. While the World Health Organization continues to promote breast-feeding in areas where no safe alternative exists, the Centers for Disease Control recommends that American women who are infected by HIV-1 not practice breast-feeding if a safe alternative is available. Large-scale, carefully controlled, prospective studies of the risk of HIV-1 infection associated with breast-feeding are of the utmost priority. Feasible and ethically acceptable feeding alternatives should be developed for countries where formula feeding has a strong negative effect on child morbidity and mortality.
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PMID:Mother-to-infant transmission of human immunodeficiency virus by breast milk: presumed innocent or presumed guilty? 144 96

Dendritic cells (DC), important antigen-presenting cells for recruiting T cells into immune responses, are susceptible to infection with HIV-1 and this can cause either stimulatory or suppressive effects on T cells. We examined another human retrovirus, HTLV-1, to determine whether DC were infected and caused any changes in T-cell function. Patients infected with HTLV-1 who have tropical spastic paraparesis (TSP) show high 'spontaneous' lymphocyte proliferation. We studied the basis for this by analyzing the interactions in vitro between lymphocytes and antigen-presenting cells and compared cells taken from HTLV-1-positive TSP patients with those taken from HTLV-1-positive healthy carriers and HTLV-1-negative family members. In HTLV-1-positive individuals, 0.4-5.1% of the DC were infected with HTLV-1 as determined by in situ hybridisation. In TSP patients, depletion of DC and purification of T cells abolished 'spontaneous' lymphocyte proliferation. Reinstating the DC, but not B cells or macrophages, restored proliferation, an effect that was blocked by antibodies either to class II major histocompatibility antigens or to HTLV-1 itself. Thus, presentation of HTLV-1 antigens by infected DC to autologous T cells could result in the abnormal T-cell proliferation and cause the inflammatory reaction leading to tissue damage in TSP. We also speculate that persistent infection of DC with HTLV-1 and consequent continuous stimulation of T cells might be instrumental in the development of HTLV-1-mediated T-cell leukemia.
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PMID:Dendritic cells from patients with tropical spastic paraparesis are infected with HTLV-1 and stimulate autologous lymphocyte proliferation. 145 15

Notable efforts have been made to relate aspects of the cell biology of T cells to the pathology, diagnosis, and treatment T-cell neoplasms. In particular, the application of molecular biologic tools to these areas has already allowed the generation of patient-specific markers for disease. A case can be made that a knowledge of the distinctive natural history of T-cell neoplasms should influence choices of treatment. Additional insights into the relevance of the human T-cell leukemia-lymphoma virus family to human disease have been recorded, and an important association of cutaneous T-cell lymphoproliferative disorders with human immunodeficiency virus infection has been documented.
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PMID:T-cell leukemia-lymphoma and mycosis fungoides. 145 97

It would require a detailed knowledge of virology, molecular biology, epidemiology, clinical medicine and politics, to appropriately compare and contrast the hypotheses on the causes of AIDS. The purpose of this review was not to do that, but to inform colleagues that alternative etiologies for AIDS have been considered. No doubt, this healthy questioning will continue until it has been demonstrated--via controlled studies of high-risk groups (both HIV positive and negative), matched for all other characteristics--that only those individuals with HIV positivity actually develop AIDS. It cannot be denied that a common theme to the hypotheses is the presence of high-risk activities. This has been used against the risk-AIDS hypothesis. How, for example, could it explain babies born with immunodeficiencies, K. Bergalis contacting AIDS from her dentist, the British nurse who died of AIDS after contracting HIV from her husband, or AIDS in the wives of hemophiliacs? It may be that these people died of specific diseases (leukemia, pneumonia, infections), which 20 years ago would have been diagnosed as such. Now, because these individuals are found to be HIV positive, they are viewed as AIDS patients. Alternatively, they may not have been asked about their nutritional status, use of psychoactive drugs, and immunosuppressive sexual practices. Additionally, it is possible that by the time AIDS was diagnosed they may have already received numerous antibiotic (immunosuppressive) drug treatments. In North America, for whatever reason, AIDS is associated with high-risk groups.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Does HIV cause AIDS? A review. 832 31

NF kappa B is a potent mediator of specific gene expression in human monocytes and has been shown to play a role in transcription of the HIV-1 genome in promonocytic leukemias. There is little information available on the response of NF kappa B to cytokines in normal human monocytes. We have used a 32P-labeled oligonucleotide derived from human immunodeficiency virus (HIV-1) long terminal repeat, which contains a tandem repeat of the NF kappa B binding sequence, as a probe in a gel retardation assay to study this transcription factor. Using this assay, we have detected NF kappa B in extracts of nuclei from normal human monocytes. Treatment of normal monocytes with 12-0-tetradecanoyl phorbol-13-acetate (TPA) for 4-24 h caused the complete disappearance of NF kappa B from nuclear extracts of monocytes. A similar result was obtained with the mature monocytic leukemia cell line THP-1. The constitutive transcription factor SP1 was unaffected by addition of TPA. The disappearance of NF kappa B from the nucleus was concentration dependent between 10 and 50 ng/ml of phorbol ester. In THP-1 cells, TPA also induced a new, faster-migrating NF kappa B species not induced in monocytes. Protein kinase C inhibitor staurosporine, but not cyclic nucleotide-dependent protein kinase inhibitor HA-1004, also dramatically reduced constitutive levels of nuclear NF kappa B. Finally, TPA addition to monocytes infected with HIV-1 inhibited HIV-1 replication, as determined by reverse transcriptase assays, in a concentration-dependent manner. These results are in striking contrast to the increase in nuclear NF kappa B and HIV-1 replication induced by phorbol esters in promonocytic leukemia cells U937 and HL-60, and emphasize the importance of studying cytokine regulation of HIV-1 in normal monocytes.
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PMID:Phorbol ester reduces constitutive nuclear NF kappa B and inhibits HIV-1 production in mature human monocytic cells. 146 36

Researchers at the US National Institutes of Health reversed their previous dismissal of the efficacy of low dose interferon alpha (Kemron) developed in Kenya against AIDS under pressure for AIDS activists and black doctors stating that at least a clinical trial should be conducted. The National Medical Association stand was similar, although it did not approve Kemron. Interferon had been discovered by a veterinary microbiologist in Texas 20 years previously, and its anticancer use was promising as it proved effective against feline leukemia in 1989. In 1989 it was administered to 204 AIDS patients in Kenya whose functional assessment increased by 66% after 10 weeks of treatment, and 18 became HIV negative. 12 other studies since then have been unable to confirm these findings, especially claims relating to seroconversion and increased CD4 cell counts. Oral interferon alpha has not been approved by the US Food and Drug Administration (FDA), but it is sold on the black market. As an FDA-approved anticancer injection drug (including against Kaposi's sarcoma often afflicting AIDS patients) its dose is 10,000 times higher than the oral dose.
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PMID:About turn in US on interferon alfa. 147 65

Vertical transmission of the human T-cell leukemia type 1 (HTLV-1) from seropositive mothers to their offspring has been extensively studied. Transmission occurs mainly through breastfeeding. Prevention relies on screening pregnant women (and wet-nurses) for HTLV-1 antibodies and advising seropositive women to refrain breast feeding. Recently, antigen detection or genome detection (using PCR) studies on lymphocytes from neonates born to HTLV-1 positive mothers have established that prenatal vertical transmission does occur, although in only a small proportion of cases (0.5 to 7%). Studies on the HTLV-1 and improved understanding of its modes of transmission may provide new insight into the transmission of the HIV.
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PMID:[Vertical transmission of HTLV-I]. 148 Apr 7

Over 50 different commercially available sulfonic acid-containing dyes were analyzed for their ability to prevent HIV-1-induced cell killing and in inhibiting HIV-1 replication. Compounds of remarkably similar structure, but with differing patterns of sulfonic acid group substitutions, had a wide range of potency in inhibiting HIV-1. Chicago sky blue (CSB) was highly effective in the inhibition of HIV-1 with less toxicity to CEM-SS cells than most of the other sulfonated dyes tested. Synthesis of CSB was undertaken to produce a product greater than 98% pure and this compound was used to elucidate the possible mechanisms by which this class of structurally related compounds inhibits HIV-1. Addition of CSB to cells infected at high multiplicity at any time up to 24 h after infection, unlike dideoxycytidine (ddC) or oxathiin carboxanilide (OC), inhibited HIV-1-induced cell killing. Other postinfection time course studies revealed that CSB had to be present for 24 h or longer immediately after infection to be protective. Virus binding to cells occurred in the presence of CSB, but the requirement for virion envelope-cell membrane fusion was delayed. CSB was a potent inhibitor of the reverse transcriptase (RT) of both HIV-1 and HIV-2, although it was less active against HIV-2 in a cell killing-based assay. CSB also inhibited Rauscher and LP-BM5 murine leukemia viruses. CSB appears to disrupt the interaction between viral proteins and cell membranes, both in the fusion step early in the infection cycle and in the development of syncytia in the late stages of virus infection.
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PMID:Sulfonic acid dyes: inhibition of the human immunodeficiency virus and mechanism of action. 151 63


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