Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.3.1.28 (chloramphenicol acetyltransferase)
 5,100 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intratracheal administration of plasmid DNA resulted in gene expression in mouse airways in the absence of any enhancing agent. Administration of plasmid DNA encoding the chloramphenicol acetyltransferase gene (CAT) in sterile water lead to CAT transgene expression that peaked between 1 and 3 days and was detected up to 28 days after DNA administration. Transgene expression was independent of mouse gender, age and strain. Levels of expression from DNA in various isotonic solutions did not differ from levels obtained with DNA administered in water, suggesting that transfection is not dependent on damage to airway cells caused by a hypo-osmotic delivery vehicle. Pharmacokinetic studies using radiolabeled plasmid DNA showed that DNA was rapidly degraded, while higher levels of radioactivity were retained for longer duration following administration of cationic liposome-DNA complexes in the airway. Southern blot and PCR analysis confirmed that DNA complexed with DOTMA-DOPE was retained in the airways for a longer period. However, cationic liposomes DOTMA-DOPE (1:1) or DOTAP complexed with DNA, did not enhance expression over DNA alone. These results suggest that 'naked' plasmid DNA should be included as a control in all studies on intratracheal gene delivery using nonviral systems.
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PMID:Intratracheal gene delivery to the mouse airway: characterization of plasmid DNA expression and pharmacokinetics. 758 23

The objectives of this study were (i) to characterize the plasmid DNA encoding the chloramphenicol acetyltransferase reporter gene (pCAT) complexed with cationic liposomes (Lipofectin and LipofectACE) in terms of particle size and zeta potential, (ii) to compare pharmacokinetic characteristics, and (iii) to study the hepatic uptake mechanisms. DNA/LipofectACE complexes showed a negative zeta potential of -36 mV at 1:5 w/w ratio, but a positive zeta potential of (19 mV at 1:10 w/w ratio. Lipofectin samples showed a positive zeta potential) of 21-28 mV at these ratios. These preparations showed a wide particle size distribution ranging from 600 to 1200 nm. Following intravenous injection of 1:10 w/w ratio [32P]pCAT/liposome complexes at a dose of 0.1 mg DNA/kg into the tail vein of mice, radioactivity was rapidly eliminated from the plasma and almost 50-60% of the dose was taken up by the liver within 5 min after administration. Plasmid DNA/liposome complexes were predominantly taken up by the liver nonparenchymal cells. The hepatic uptake was inhibited by preceding administration of dextran sulfate (DS), but not by polycytidic acid (poly[C]) and polyinosinic acid (poly[I]), suggesting the involvement of a phagocytic process. We suggest that these complexes are preferentially taken up by the liver nonparenchymal cells mainly via Kupffer cell phagocytosis.
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PMID:Physicochemical and pharmacokinetic characteristics of plasmid DNA/cationic liposome complexes. 858 40

Long-term expression of a reporter gene has previously been reported in skeletal and cardiac muscles after direct injection of naked plasmid DNA. In this study, we have shown that the direct injection of free plasmid DNA into mouse melanoma BL6 solid tumor can also result in a high level of transfection. THe average amount of chloramphenicol acetyltransferase (CAT) expressed by injecting 30 micrograms plasmid DNA containing a CAT gene into a single BL6 tumor was 1.9 +/- 1.0 ng, which is comparable to that reported in the skeletal muscle. Cationic liposomes, Lipofectamine and DC-chol/DOPE, inhibited gene expression in a dose-dependent manner. Transgene expression by free DNA persisted for at least 10 days. The size of tumor did not seem to affect the gene expression, but proper choice of a diluent solution for DNA was an important factor. Genes driven by the CMV promoter were expressed much more efficiently than genes driven by the SV40 or T7 promoter. Optimal dosage of injected DNA was from 30 to 70 micrograms per tumor. Other mouse melanomas, human melanomas and cervical carcinomas are also able to express directly injected plasmid DNA, but the transfection efficiency is lower than the BL6 tumor. Direct injection of free plasmid DNA is a simple and effective approach and might be a potential method for cancer gene therapy.
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PMID:Direct gene transfer to mouse melanoma by intratumor injection of free DNA. 878 4

Although gene delivery to the pulmonary circulation has both experimental and therapeutic potential, the delivery methods, distribution of transgene, and subsequent inflammatory response have been poorly characterized to date. To address these issues, we utilized a 0.76-mm OD (outside diameter) end hole catheter inserted into the internal jugular vein of adult Sprague-Dawley rats, directing the tip into a pulmonary capillary wedge position. We then compared infusion of polycationic lipid:DNA complexes to replication-defective adenovirus with respect to magnitude and distribution of transgene expression using either chloramphenicol acetyltransferase (CAT) or human placental alkaline phosphatase (hpAP) reporter genes. Both lipid:DNA and adenovirus resulted in detectable transgene expression, though maximum lung CAT activity using lipid (gamma AP-DLRIE/DOPE) was approximately 2% of maximum activity using adenovirus (Ad-CAT). Further characterization of expression after transfection with 10(8) pfu (plaque forming units) of Ad-CAT demonstrated persistence of transgene for at least 14 days (lung CAT activity 27% of maximum). Alkaline phosphatase staining demonstrated that both large and small pulmonary arteries as well as the alveolar wall expressed transgene. Although little inflammatory response was detected in conduit arteries, a predominantly mononuclear cell infiltrate surrounded small pulmonary arteries as well as the alveolar spaces in transfected areas of lung. We conclude that percutaneous catheter-mediated gene delivery to the pulmonary circulation in rats using non-viral and viral vectors is feasible. Although an inflammatory response to first generation replication-defective adenovirus was detected, it appeared to be largely restricted to the distal pulmonary circulation and airspace. This technique should prove useful for investigations requiring overexpression of novel genes in the pulmonary artery wall, and could ultimately be used to develop gene-based therapies for pulmonary vascular diseases.
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PMID:In vivo gene delivery to the pulmonary circulation in rats: transgene distribution and vascular inflammatory response. 919 65

Intratracheal (i.t.) and intravenous (i.v.) delivery of DNA-vector formulations are two strategies to obtain gene transfer to the lung, it is still uncertain, however, which of these two modes of delivery will be more effective in the treatment of cystic fibrosis and other lung diseases. In this study, we attempted to optimize formulations of the cationic liposome DODAC:DOPE (dioleoyldimethylammonium-chloride: dioleoylphosphatidylethanolamine) complexed to plasmids encoding chloramphenicol acetyltransferase for i.t. and i.v. injection into CD-2 mice and compared the two methods. Our results showed that both methods conferred reporter gene expression in the lung that was significantly higher relative to injection of plasmid DNA alone. Expression using either mode of administration was maximal 24 h after injection and declined to around 10% of day 1 levels 2 weeks after injection. For i.v. delivery of DODAC. DOPE-DNA complexes multilamellar vesicles were more effective than large unilamellar vesicles in all organs investigated. Recombinant DNA could be detected in the distal lung region following either route of administration. However, i.t. administration predominantly led to DNA deposition in epithelial cells lining the bronchioles, e.g. in clara cells, whereas i.v. administration resulted in DNA deposition in the alveolar region of the lung including type II alveolar epithelial cells.
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PMID:Comparison between intratracheal and intravenous administration of liposome-DNA complexes for cystic fibrosis lung gene therapy. 957 37