No abstract available.
Humans ; Ulcer* ; Zidovudine*

No abstract available.
HIV* ; Humans ; Humans* ; Lymphocytes* ; Zidovudine*

Background : Gene transfer with vectors derived from murine retroviruses is restricted to cells which are proliferating and synthesizing DNA at the time of infection. Accordingly, selective introduction of genes encoding for susceptibility to otherwise nontoxic drugs (suicide genes) into proliferating tumor may be used to treat cancer. We investigated the efficacy of in vitro transduction of neuroblastoma cell with the herpes simplex-thymidine kinase (HSV-tk) gene followed by administration of the antiviral drug ganciclovir. METHODS: The LNC/tK vector was transfered in vitro into mouse Neuro 2a cell lines (ATCC) and the transduced cell lines were selected in G-418, 500microgram/ml, for 14 days. Onex104 cells were cultured in 96 well culture plates in increasing concentrations of ganciclovir for 72 hours. The sesitivity to ganciclivir of these HSV-tk transduced, G-418 selected cells was measured with MTT assay RESULTS: The survival of HSV-tk transduced 1x104 neuro 2a cell lines is 103+/-3.5%, 68+/-4.2%, 54+/-3.8%, 17+/-2.6%, 13+/-3.1% at the concentration of 0, 0.1, 1.0, 10, 20microgram/ml ganciclovir, respectively. And the survival of HSV-tk not transduced 1x104 neuro 2a cell lines is 100+/-4.5%, 97+/-5.6%, 104+/-3.5%, 106+/-3.8%, 101+/-4.2%. CONCLUSION: We concluded that in vitro transduction of neuroblastoma cell with the herpes simplex-thymidine kinase gene followed by administration of the antiviral drug ganciclovir is very effective.
Animals ; Cell Line* ; DNA ; Ganciclovir ; Mice ; Neuroblastoma* ; Phosphotransferases ; Retroviridae ; Zidovudine*

Background : Gene transfer with vectors derived from murine retroviruses is restricted to cells which are proliferating and synthesizing DNA at the time of infection. Accordingly, selective introduction of genes encoding for susceptibility to otherwise nontoxic drugs (suicide genes) into proliferating tumor may be used to treat cancer. We investigated the efficacy of in vitro transduction of neuroblastoma cell with the herpes simplex-thymidine kinase (HSV-tk) gene followed by administration of the antiviral drug ganciclovir. METHODS: The LNC/tK vector was transfered in vitro into mouse Neuro 2a cell lines (ATCC) and the transduced cell lines were selected in G-418, 500microgram/ml, for 14 days. Onex104 cells were cultured in 96 well culture plates in increasing concentrations of ganciclovir for 72 hours. The sesitivity to ganciclivir of these HSV-tk transduced, G-418 selected cells was measured with MTT assay RESULTS: The survival of HSV-tk transduced 1x104 neuro 2a cell lines is 103+/-3.5%, 68+/-4.2%, 54+/-3.8%, 17+/-2.6%, 13+/-3.1% at the concentration of 0, 0.1, 1.0, 10, 20microgram/ml ganciclovir, respectively. And the survival of HSV-tk not transduced 1x104 neuro 2a cell lines is 100+/-4.5%, 97+/-5.6%, 104+/-3.5%, 106+/-3.8%, 101+/-4.2%. CONCLUSION: We concluded that in vitro transduction of neuroblastoma cell with the herpes simplex-thymidine kinase gene followed by administration of the antiviral drug ganciclovir is very effective.
Animals ; Cell Line* ; DNA ; Ganciclovir ; Mice ; Neuroblastoma* ; Phosphotransferases ; Retroviridae ; Zidovudine*

No abstract available.
Genes, pol* ; HIV-1 ; Humans* ; RNA-Directed DNA Polymerase ; Zidovudine*

To investigate resistance to lamivudine (3TC), we examined the incidence of M184V in 20 HIV-1 patients treated with 3TC for 13.1 +/- 9 months. Fourteen of 20 patients had been exposed to zidovudine (ZDV) or didanosine (ddl) prior to 3TC therapy. Nested PCR targeting to reverse transcriptase (RT) and direct sequencing were performed for peripheral blood mononuclear cells sampled serially. There were resistance mutations to ZDV in at least 9 patients at baseline, although there was no resistance mutation to 3TC. We could detect M184V in 6 (30%) out of 20 patients. The incidence of M184V increased as the duration of therapy prolongs (13% in samples<12 months; 47% in samples gtoreq 12 months). The frequency of mutation M184V was higher in patients with previous mutation to ZDV than in patients with wild type. Resistance mutation was not detected in 7 patients. This study shows that resistance to 3TC tends to develop rapidly in patients with baseline mutations or two drugs combination therapy than in those treated simultaneously with triple drugs. This report is the first on resistance to 3TC in Korean AIDS patients.
Didanosine ; HIV-1* ; Humans ; Incidence ; Lamivudine* ; Polymerase Chain Reaction ; RNA-Directed DNA Polymerase ; Zidovudine

Despite advances in neurosurgery, radiation, and chemotherapy, the prognosis of patients with malignant brain tumors still remains grim. Considerable efforts have been made to develop new therapeutic strategies for malignant brain tumors. One of the promising new therapies for brain tumors is an intervention at molecular level, and several molecular approaches have been shown to have in vitro and in vivo activities. These include the use of retroviral vectors, herpes simplex viruses, adenoviral vectors in gene transfer, and antisense vectors and oligonucleotides. Preclinical studies of retroviral vector have already been extended to clinical trials, clearly demonstrating the clinical potential of these molecular therapies. Here, I discuss the current status of molecular therapy for brain tumors together with future directions for its development.
Brain Neoplasms* ; Brain* ; Drug Therapy ; Humans ; Neurosurgery ; Oligonucleotides ; Oligonucleotides, Antisense* ; Prognosis ; Simplexvirus ; Zidovudine

To examine AZT resistance of HIV-1 isolates from AZT treated or untreated Korean, several biological characteristics such as syncytium formation, HIV-1 reverse transcriptase activity and the p24 antigen production in MT-2 cells infected with 4 HRT_1 isolates were determined. As controls, we tested HIV-1 HTLV-IIIB and pre-drug isolate as AZT susceptible strains, in addition to HIV-1 RTMC/MT-2 and post-drug isolate as AZT resistant strains. When the inoculum size of HIV-1 was 300 TCID50well and 100 TCID50/well, the AZT susceptibility of AZT untreated HIV-1 isolates 8806 and 9571 were similar to that of HIV-1 HTLV-IIIB and AZT-susceptible HIV-1 strains. When we evaluated AZT resistance of isolates HRs-1 8812 and 9113 treated with AZT for 36 months by observation of syncytium formation, HIV-1 8812 showed resistance simillar to that of HIV-1 RTMC/MT-2 strain forming syncytium up to AZT 1microgram/ml, and HIV-1 9113 showed resistance identical with that of AZT-resistant HIV-1 strain which formed syncytium up to AZT 10 microgram/ml. Especially, when we evaluated AZT resistance by HIV-1 reverse transcriptase activty and the p24 antigen production, HIV-1 isolates 8812 and 9113 showed much higher resistance (>10 - 200 fold) compared with HN-1 RTMC/MT-2 and AZT-resistant HIV-1 strain.
Giant Cells ; HIV-1* ; Korea* ; Population Characteristics ; RNA-Directed DNA Polymerase ; Zidovudine*

BACKGROUND AND OBJECTIVES: Compared to other target cells examined for gene therapy, vascular smooth muscle cells (VSMCs) have the unique advantages including proximity to blood stream and relative abundance in vasculature. With an ultimate goal of developing VSMC-based therapies for cardiovascular disorders, we explored the utility of VSMC as a target cell for ex vivo gene therapy using a set of retroviral vectors. MATERIALS AND METHODS: Cultured VSMCs were transduced with replication-defective recombinant retroviruses harboring LacZ, nlsLacZ, mVEGF, mGM-CSF or bacterial CAT reporter. The VSMCs were examined for G418-selection, transduction efficiency, the level of transgene expression, and longevity of gene expression. ResultsVSMCs were readily transduced with different kinds of retroviral vectors. The bacterial neo r gene-transduced VSMCs were successfully selected with G418. The G418-selected VSMCs could express the transduced genes at a level comparable to NIH3T3. The level of transgene expression did not appear to be affected by the increasing number of passages. CONCLUSION: The results demonstrate an efficient transduction of VSMCs by retroviral vectors in vitro and an sustained expression of retrovirally transduced genes in VSMCs. VSMCs could be one of the ideal target cells for ex vivo cardiovascular gene therapy employing retroviral vector.
Animals ; Cats ; Gene Expression ; Genetic Therapy* ; Longevity ; Muscle, Smooth, Vascular* ; Retroviridae ; Rivers ; Transgenes ; Zidovudine

Background: WDR1 is thought to be correlating with polymerization and depolymerization of actin protein. Though WDR1 was found to be within nucleus, in which actin could not be present by previous studies, the exact distribution pattern of WDR1 protein under various circumstances was not elucidated up to the present time. In this regard, we tried to see a change in the distribution of WDR1 protein within artificially induced senescent PC 12 pheochromocytoma cells for the first time. Methods: PC12 pheochromocytoma cells (ATCC CRL-1721) were grown in the culture media including 1 micrometer 3'-Azido-3'-deoxythymidine (AZT, Sigma-Aldrich, USA). The senescence of the cells was confirmed by senescence detection kit (Calbiochem, San Diego, CA). Immunocytochemical study by using WDR1 antibody was also performed in the cells treated with AZT during 0, 75 and 153 days. Results: WDR1 protein was mainly observed within the cytoplasm of the cells not treated with AZT. However, the distribution of the same protein was changed into the nucleus after 153 day-AZT treatment. Conclusion: The distribution of WDR1 protein was changed into nucleus in the artificially senescent PC12 cells.
Actins ; Aging ; Animals ; Culture Media ; Cytoplasm ; PC12 Cells* ; Pheochromocytoma ; Polymerization ; Polymers ; Zidovudine