Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1261473 (sarcoma)
 25,952 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

9-(2-Phosphonylmethoxyethyl)adenine (PMEA), a potent inhibitor of human immunodeficiency virus (HIV), caused a dose-dependent suppression of tumor formation, and mortality associated therewith, in 6-day-old NMRI mice inoculated intracerebrally with Moloney murine sarcoma virus (MSV). Even at a dose as low as 1 mg/kg/day, PMEA effected a significant delay in tumor formation. When evaluated in parallel with PMEA, 3'-azido-2',3'-dideoxythymidine (AZT) conferred a comparable tumor-inhibitory effect at a 5- to 10-fold higher dose than PMEA. Prolonged treatment of MSV-infected mice with PMEA resulted in long-term survivors without apparent signs of tumor development. In view of the propensity of HIV to spread to the central nervous system (CNS), the marked activity shown by PMEA against experimental retrovirus infection of the brain in mice points to its potential in the treatment of AIDS and other retrovirus infections of the CNS.
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PMID:Inhibitory effects of 9-(2-phosphonylmethoxyethyl)adenine and 3'-azido-2',3'-dideoxythymidine on tumor development in mice inoculated intracerebrally with Moloney murine sarcoma virus. 230 39

Different treatment schedules have been investigated when evaluating the inhibitory effect of 9-(2-phosphonylmethoxyethyl)adenine (PMEA) and 3'-azido-2',3'-dideoxythymidine (AZT) on the replication of human immunodeficiency virus type I (HIV-I) in MT-4 cells, transformation of C3H/3T3 cells by Moloney murine sarcoma virus (MSV), and MSV-induced tumor formation in newborn NMRI mice. Shortening the exposure time of HIV-I-infected MT-4 cells to PMEA or AZT led to an increase in the selectivity index of both compounds. PMEA proved markedly more efficient in suppressing MSV-induced tumor formation in mice when administered as a single dose on the day of infection than when these doses were spread over 2, 4 or 7 administrations within 1 week after the virus infection. This was not observed when the total dose of AZT was fractionated. While the infrequent dosage regimen increased the anti-retrovirus activity of PMEA, it did not increase its toxicity for the host. This unique property makes PMEA an attractive candidate for the treatment of retrovirus infections, including AIDS.
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PMID:Anti-retrovirus activity of 9-(2-phosphonylmethoxyethyl)adenine (PMEA) in vivo increases when it is less frequently administered. 238 80

A series of 5'-phosphorylated derivatives of 3'-azido-2',3'-dideoxythymidine (AzddThd), including AzddThd 5'-mono- and 5'-triphosphate, alpha, beta-methylene AzddThd-5'-diphosphate, alpha,beta-methylene AzddThd-5'-triphosphate, and beta,gamma-methylene AzddThd-5'-triphosphate, were evaluated for their cytostatic and anti-retrovirus properties, and their inhibitory effects on the reverse transcriptases of Moloney murine leukemia virus and human immunodeficiency virus. In contrast with the 5'-mono- and 5'-triphosphates of AzddThd, which showed cytostatic and anti-retrovirus activities comparable to those of AzddThd, the alpha,beta-methylene 5'-phosphonates of AzddThd were considerably less cytostatic and also much less inhibitory to cell transformation by Moloney murine sarcoma virus and cytopathogenicity of human immunodeficiency virus. The decreased biological activity of the phosphonate derivatives of AzddThd is most likely due to the resistance of these compounds to phosphorolytic attack by phosphodiesterases and phosphatases, and the reduced affinity for the retrovirus-associated reverse transcriptase.
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PMID:Alpha, beta- and beta, gamma-methylene 5'-phosphonate derivatives of 3'-azido-2',3'-dideoxythymidine-5'-triphosphate. Correlation between affinity for reverse transcriptase, susceptibility to hydrolysis by phosphodiesterases and anti-retrovirus activity. 245 21

Co-administration of soluble Ag and anti-CD4 mAb has been successfully used to induce long term Ag-specific tolerance. The mechanisms underlying persistent immunologic unresponsiveness are unclear. We have now studied whether tolerance toward complex viral Ag expressed on Moloney sarcoma virus (MSV)-transformed tumor cells can be induced when given at the time of severe helper cell depletion. Although mice that had been injected with anti-CD4 mAb at the time of immunization regained the ability to recognize MSV Ag, their humoral and cytotoxic immunity to MSV were severely compromised. Ag-specific low responsiveness was maintained for more than 6 mo. To analyze the T cell repertoire of low responder mice we have estimated precursor frequencies of MSV-specific proliferative and cytotoxic T cells after the CD4+ T cell subset was fully reconstituted. There was no difference in the frequencies of control and low responder mice excluding clonal deletion as the mechanism maintaining low responsiveness. In co-culture experiments the defect in low responder mice could be localized to the regenerated CD4+ T cell subset, suggesting the induction of CD4+ suppressor-inducer cells. Alternatively, regenerated CD4+ cells in anti-CD4 conditioned mice had acquired a defect to provide help for MSV-specific responses. In spite of the potentials to induce low responsiveness to selected Ag by anti-CD4 conditioning, the risk to cause persistent virus-specific immunodeficiency might limit the clinical application of anti-CD4 therapy.
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PMID:Persistent suppression of virus-specific cytotoxic T cell responses after transient depletion of CD4+ T cells in vivo. 280 9

3'-Azido-2',3'-dideoxythymidine (AZT) and 2',3'-didehydro-2',3'-dideoxythymidine (D4T) are potent and selective inhibitors of human immunodeficiency virus replication in MT-4 and ATH8 cells. They are also inhibitory to the replication of murine retroviruses, i.e. Moloney murine sarcoma virus-induced transformation of C3H cells. In MT-4 cells AZT is readily phosphorylated to its 5'-monophosphate, while the 5'-di- and 5'-triphosphates are generated to a 200-600-fold lower extent than the 5'-monophosphate. D4T is phosphorylated in MT-4 cells to its 5'-monophosphate at a 300-600-fold lower extent than AZT. The phosphorylation of AZT in the thymidine kinase-deficient cell line (Raji/TK-) is severely depressed, while D4T phosphorylation is only slightly diminished in Raji/TK- as compared to Raji/0 cells. D4T has a 10-fold lower affinity for phosphorylation by crude MT-4 cell extracts than AZT (Km, 142 and 14 microM, respectively), and the Vmax for phosphorylation of D4T is only 5% that of AZT. D4T is phosphorylated by MT-4 cell extracts about 180-fold less efficiently than AZT (Vmax/Km, 0.06 for D4T, as compared to 11 for AZT), and this is consistent with the differences found in the amounts of phosphorylated products of D4T and AZT formed in intact MT-4 cells. The 5'-triphosphates of AZT and D4T are equipotent in their inhibitory effects on the reverse transcriptases from human immunodeficiency virus and Moloney murine leukemia virus.
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PMID:Differential patterns of intracellular metabolism of 2',3'-didehydro-2',3'-dideoxythymidine and 3'-azido-2',3'-dideoxythymidine, two potent anti-human immunodeficiency virus compounds. 253 71

Nine instances of oral non-Hodgkin's lymphoma occurring in homosexual male patients infected with the human immunodeficiency virus were evaluated for clinical features, histopathologic features, lymphocyte phenotypic markers, and Epstein-Barr virus (EBV) DNA. Histologically, the tumors represented immunoblastic sarcoma and small noncleaved cell lymphomas, some manifesting Burkitt-like features. Five cases exhibited positive staining with monoclonal antibody L26, a B-cell marker; none of the tumors showed evidence of a T-cell lineage with the use of monoclonal antibody UCHL 1. DNA in situ hybridization studies disclosed the presence of EBV DNA sequences in seven instances. These findings indicate that most oral lymphomas among patients with AIDS, similar to extraoral lymphomas in this population, are of B-cell lineage and harbor EBV DNA.
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PMID:Oral lymphomas in HIV-infected patients: association with Epstein-Barr virus DNA. 254 61

3'-Azido-2,6-diaminopurine-2',3'-dideoxyriboside (AzddDAPR) is a potent and selective inhibitor of human immunodeficiency virus (HIV) replication in vitro. It also inhibits Moloney murine sarcoma virus (MSV)-induced transformation of murine C3H/3T3 embryo fibroblasts. AzddDAPR causes a marked dose-dependent suppression of MSV-induced tumor formation and mortality therewith associated in newborn mice infected with MSV. Combination of AzddDAPR with ribavirin resulted in a marked potentiation of its anti-retrovirus activity in vitro and a significant enhancement of its inhibitory effect on MSV-induced tumor formation in vivo. A slight increase in the in vivo toxicity of AzddDAPR was noted when combined with ribavirin.
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PMID:Potentiating effect of ribavirin on the anti-retrovirus activity of 3'-azido-2,6-diaminopurine-2',3'-dideoxyriboside in vitro and in vivo. 254 63

9-(2-phosphonylmethoxyethyl)-2,6-diaminopurine (PMEDAP) is a potent inhibitor of the replication of human immunodeficiency virus (HIV) in human T-lymphocyte MT-4 cells (50% effective dose: 2 microM). PMEDAP strongly inhibited Moloney murine sarcoma virus (MSV)-induced transformation of murine C3H/3T3 embryo fibroblasts and caused a dose-dependent suppression of tumor formation and mortality in newborn mice inoculated with MSV. Even at a dose as low as 0.25 mg/kg/day, PMEDAP effected a significant delay in tumor appearance and an enhancement of the survival rate of tumor-bearing mice. PMEDAP proved fivefold more efficacious as an anti-MSV agent than 9-(2-phosphonylmethoxyethyl)-adenine (PMEA), which has been previously shown to exhibit strong antiretroviral efficacy in vivo. However, PMEDAP was also more toxic, so that its therapeutic index was equivalent to that of PMEA.
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PMID:9-(2-Phosphonylmethoxyethyl)-2,6-diaminopurine (PMEDAP): a novel agent with anti-human immunodeficiency virus activity in vitro and potent anti-Moloney murine sarcoma virus activity in vivo. 255 45

The novel 5-chloro-, 5-bromo-, and 5-iodo-derivatives of 3'-fluoro-2',3'-dideoxyuridine (FddUrd), designated FddCIUrd, FddBrUrd, and FddIUrd, respectively, have been synthesized and evaluated for their antiretrovirus activity against human immunodeficiency virus (HIV) and murine Moloney sarcoma virus. All three 5-halogeno-FddUrd analogues inhibited HIV-1 replication in MT4 cells with an effective dose (ED50) of about 0.2-0.4 microM. However, FddCIUrd was markedly more selective in its anti-HIV-1 activity than FddBrUrd or FddIUrd. The selectivity index of FddCIUrd was similar to that of 3'-azido-2',3'-dideoxythymidine (AZT) when evaluated in parallel (1408 and 1603, respectively). The FddUrd derivatives also had a marked inhibitory effect on HIV-2 replication in MT4 cells and HIV-1 induced antigen expression in HUT-78 cells. However, neither FddUrd nor its 5-halogeno derivatives were inhibitory to Moloney sarcoma virus-induced transformation of murine C3H cells. The anti-HIV-1 activity of FddUrd, FddCIUrd, FddBrUrd, and FddIUrd was reversed by the addition of thymidine and 2'-deoxycytidine. The 5-halogeno-FddUrd analogues had a markedly higher affinity for MT4 thymidine kinase than FddUrd (Ki/Km, 4.0-4.7, as compared with 302 for FddUrd).
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PMID:5-Halogeno-3'-fluoro-2',3'-dideoxyuridines as inhibitors of human immunodeficiency virus (HIV): potent and selective anti-HIV activity of 3'-fluoro-2',3'-dideoxy-5-chlorouridine. 272 68

A series of 3'-C-cyano-3'-deoxynucleosides have been synthesized and evaluated as antiviral agents. Reaction of 2',5'-bis-O-(tert-butyldimethylsilyl)-beta-D-erythro-pentofuranos- 3'-ulosyl derivatives of uracil, 4-N-acetylcytosine, and adenine with sodium cyanide gave a mixture of epimeric cyanohydrins, which after 3'-deoxygenation yielded the corresponding 3'-C-cyano-3'-deoxy-beta-D-xylo-pentofuranosyl derivatives 10. These compounds were epimerized to the corresponding beta-D-ribo-pentofuranosyl derivatives 11. Desilylation of 10 and 11 gave the deprotected 3'-C-cyano-3'-deoxy-beta-D-xylo- and -ribo-pentofuranosyl nucleosides. These derivatives of uridine, cytidine, and adenine, as well as the 3'-C-cyano-3'-deoxy-beta-D-xylo- and -ribo-pentofuranosyl, 3'-C-cyano-2',3'-dideoxy-beta-D-threo- and -erythro-pentofuranosyl, and 3'-C-cyano-2',3'-dideoxy-beta-D-glycero-pent-2'-enofuranosyl derivatives of thymine, were evaluated for their antiviral activity. None of the compounds proved active against the replication of retroviruses (human immunodeficiency virus, murine sarcoma virus) at concentrations that were not toxic to the host cells. However, the 3'-C-cyano-3'-deoxy-beta-D-xylo- (12e) and -ribo-pentofuranosyl (13e) derivatives of adenine showed activity against some DNA (i.e., vaccinia) and RNA (i.e., Sindbis, Semliki forest) viruses at concentrations well below the cytotoxicity threshold.
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PMID:Synthesis and antiviral activity of 3'-C-cyano-3'-deoxynucleosides. 275 98


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