No abstract available.
Humans ; Ulcer* ; Zidovudine*

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

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

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

Retroviral vector provide a highly efficient method for gene transfer into eukaryotic cells. This vector system can be divided into two components; the retroviral vector itself and the retroviral packaging cell line. The key improvement in the design of these two components are. focused on two aspects; the reduction of helper virus production and high titer-virus. We used PA317 for retrovirus packaging cell line, for its high producibility of viral titer, To test the ability of the vectors to generate high titer-virus, we have chosen four different retroviral vectors; LN, LNSX, LNCX and LXSN. To test easily the viral titer, we have made recombinant construction with CD4 and CD8, checked their viral titer and stained their surface expression. LXSN which contain SV40 early promoter in front of leo gene showed best results in viral transient transfection assay, dot blot assay and surface expression. In addition, recombinant containing CD8 generally showed much higher viral titration and surface expression than CD4.
Cell Line ; Eukaryotic Cells ; Helper Viruses ; Product Packaging ; Retroviridae ; Transfection ; Zidovudine*

BACKGROUND: The CCAAT/enhancer binding protein epsilon (C/EBPepsilon), one of the transcription factors, plays an important role in granulopoiesis. We examined an essential site of C/EBP epsilon for granulopoiesis. METHODS: 32Dcl3 cells and #1111 cells were transduced with retroviral constructs of C/EBP epsilon and C/EBP epsilon(R211A) (DNA binding mutant form). We examined growth rate, checked the neutrophil markers of Gr-1 and Mac-1, and counted differentiated cells in the transduced 32Dcl3 cells. The transduced #1111 cells were injected into five mice and survival times were analyzed. RESULTS: The mean number of green fluorescent protein (GFP) (+) 32Dcl3 cells transduced with C/EBP was 244, 045 at day 2, 582, 938 at day 4, and 873, 963 at day 6; mean expression of Gr-1 was 31.3% and Mac-1 32.6%; mean count of immature form was 41.0%, intermediate form 48.3%, and mature form 10.7%. In case of C/EBP epsilon (R211A) transduced 32Dcl3 cells, the respective figures were 707, 226, 1, 106, 736, and 2, 133, 819; 0.1% and 0.1%; and 91.7%, 4.3%, and 4.0%. The mean survival time of #1111 cells transduced with C/EBP epsilon was 26.0 days in placebo group and 34.0 days in 4-hydroxytamoxifen (4HT; C/EBP epsilon group); in case of C/EBP epsilon(R211A) transduced #1111 cells, the respective figures were 36.4 and 37.4 days. CONCLUSIONS: The growth of 32Dcl3 and #1111 cells was inhibited by C/EBP epsilon, but not by C/EBP epsilon(R211A). Also C/EBP epsilon was involved in the differentiation of 32Dcl3 cells, but C/EBP epsilon(R211A) was not. The DNA binding domain of C/EBP epsilon is a very important site for differentiating and inhibiting early myeloid cells.
Animals ; Carrier Proteins ; DNA* ; Mice ; Myeloid Cells ; Neutrophils ; Survival Rate ; Transcription Factors ; 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*

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