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  • muscle  (2)
  • block copolymers  (1)
  • cationic lipids  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Pharmaceutical research 12 (1995), S. 1435-1438 
    ISSN: 1573-904X
    Keywords: surface tension ; micelles ; block copolymers ; phagocytosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. This work was carried out to determine the surface tension of block copolymer micelles of 14C labelled ABA poly (oxyethylene-bi-isoprene-b-oxyethylene) which have a long circulating half life in animals. Methods. The method used was that of phagocytosis. The percentage of micelles phagocytosed by human mononuclear cells was determined in solutions of different surface tension. Results. The values obtained were 72 mN/m which may be predicted for a particle with a long circulating half life in animals. The method also gave an estimate of the surface tension for the mononuclear cells. Conclusions. This technique has the advantage of determining the surface tension of highly hydrated small particles including stable micelles in an environment similar to that in which they normally exist.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-904X
    Keywords: muscle ; genetic vaccines ; immune response ; polyvinylpyrrolidone ; growth hormone ; and needle-free injection device
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. A plasmid-based gene expression system was complexed with protective, interactive, and non-condensing (PINC™) polymer system and administered with Medi-Jector™, a needle-free injection device (NFID), to achieve high and sustained levels of antigen-specific antibodies in blood circulation. Methods. Human growth hormone (hGH) or bacterial β-galactosidase gene expression plasmids driven by a cytomegalovirus (CMV) promoter were formulated in saline or complexed with a PINC polymer, polyvinylpyrrolidone (PVP), and intramuscularly or subcutaneously administered into dogs and pigs using a 22-gauge needle or a NFID. The hGH-specific IgG titers in serum were measured by an ELISA. β-galactosidase expression was measured in injected muscles by an enzymatic assay or immunohistochemistry. The effect of NFID on DNA stability and topology was assessed by gel electrophoresis. Results. Intramuscular (i.m.) or subcutaneous (s.c.) injection of a hGH expression plasmid pCMV-hGH (0.05-0.5 mg/kg) in dogs and pigs elicited antigen-specific IgG antibody titers to expressed hGH. With both routes of injection, pDNA delivery by a NFID was superior to pDNA injection by needle. The magnitude of hGH-specific IgG titers with NFID was 15−20-fold higher than needle injection when pDNA was complexed with PVP, and only 3−4-fold higher with pDNA in saline. The transfection efficiency in the injected muscle, as measured by β-galaclosidase expression, following i.m. injection of pCMV-β-galaclosidase/PVP, was not significantly different between needle and NFID-injected groups. Conclusions. These data demonstrate that the combination of pDNA/ PVP complexes and a NFID act synergistically to achieve high and sustained levels of antigen-specific IgG response to expressed antigen. This gene delivery approach may offer advantage over needle injection of naked DNA for the development of genetic vaccines.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1573-904X
    Keywords: muscle ; DNA plasmid ; gene delivery system ; polyvinyl pyrrolidone ; polyvinyl alcohol ; non-viral gene therapy ; gene expression system
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. DNA plasmids (pDNA) can be taken up by and expressed in striated muscle after direct intramuscular injection. We have developed interactive polymeric gene delivery systems that increase pDNA bioavailability to muscle cells by both protecting pDNA from nucleases and controlling the dispersion and retention of pDNA in muscle tissue. Methods. A DNA plasmid, containing a CMV promoter and a β-galactosidase reporter gene (CMV-β-gal), was injected either in saline or formulated in polyvinyl pyrrolidone (PVP) and polyvinyl alcohol (PVA) solutions. Interactions between PVP and pDNA were assessed by dynamic dialysis, Isothermal Titration Calorimetry (ITC), and Fourier-Transformed Infra Red (FT-IR) spectroscopy. Formulations (50 µl) were injected into rat tibialis muscles after surgical exposure. Immuno-histochemistry for β-gal was used to visualize the sites of expression in muscle. Results. β-gal expression using pDNA in saline reached a plateau while β-gal expression using PVP formulations increased linearly in the dose range studied (12.5–150 µg pDNA injected) and resulted in an increase in the number and distribution of cells expressing β-gal. The interaction between PVP and pDNA was found to be an endothermic process governed largely by hydrogen-bonding and results in protection of pDNA from extracellular nucleases. Conclusions. Significant enhancement of gene expression using interactive polyvinyl-based delivery systems has been observed. The improved tissue dispersion and cellular uptake of pDNA using polyvinyl-based systems after direct injection into muscle is possibly due to osmotic effects.
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  • 4
    ISSN: 1573-904X
    Keywords: gene transfer ; airways ; cationic lipids ; surface charge ; co-lipid content ; topology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Cationic lipids are capable of transferring foreign genes to the pulmonary epithelium in vivo. It is becoming increasingly clear that factors other than lipid molecular structure also influence efficiency of delivery using cationic lipid systems. This study is aimed at evaluating the effect of formulation variables such as cationic lipid structure, cationic lipid/DNA ratio, particle size, co-lipid content and plasmid topology on transgene expression in the lung. Methods. The effect of varying the surface and colloidal properties of cationic lipid-based gene delivery systems was assessed by intratracheal instillation into rats. An expression plasmid encoding chloramphenicol acetyl transferase (CAT) was used to measure transgene expression. Results. Cationic lipid structure, cationic lipid/DNA ratio, particle size, co-lipid content and topology of the plasmid, were found to significantly affect transgene expression. Complexation with lipids was found to have a protective effect on DNA integrity in bronchoalveolar lavage fluid (BALF). DNA complexed with lipid showed enhanced persistence in rat lungs as measured by quantitative polymerase chain reaction. Conclusions. Fluorescence microscopy analysis indicated that the instilled formulation reaches the lower airways and alveolar region. Data also suggests cationic lipid-mediated gene expression is primarily localized in the lung parenchyma and not infiltrating cells isolated from the BALF.
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