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Maguire LA, Zhang H, Shamlou PA. Preparation of small unilamellar vesicles (SUV) and biophysical characterization of their complexes with poly-l-lysine-condensed plasmid DNA. Biotechnol Appl Biochem 2003; 37:73-81. [PMID: 12578554 DOI: 10.1042/ba20020107] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Liposomes have numerous applications in the (bio)pharmaceutical industries as agents in the synthesis of new biomaterials for use in areas including gene delivery. There is currently a need to establish efficient scaleable methods for the manufacture of liposomes, and in the present paper we describe the operation of a new high-velocity jet homogenizer for downsizing of multilamellar large vesicles to produce small unilamellar vesicles (SUV). Measurements of size distribution of SUVs are presented and compared with mathematical simulations based on the solution of a population balance equation combined with computational-fluid-dynamics analysis of flow in the homogenizer. Anionic SUVs are produced by the new method and incubated with poly-L-lysine (PLL)-condensed plasmid DNA (pDNA) to generate complexes under different physico-chemical conditions. The colloidal properties of the resulting complexes, including their size and charge, are measured using a Zetasizer and the encapsulation efficiency is obtained experimentally using a Pico Green assay. The results show that between 85 and 95% of the PLL-pDNA condensed plasmids were encapsulated by the liposomes, the smaller liposomes being more effective in encapsulating the complexes.
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Scott BL, Van Komen JS, Liu S, Weber T, Melia TJ, McNew JA. Liposome fusion assay to monitor intracellular membrane fusion machines. Methods Enzymol 2003. [PMID: 14610819 DOI: 10.1016/s0076-6879(03)72016-72013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
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Scott BL, Van Komen JS, Liu S, Weber T, Melia TJ, McNew JA. Liposome fusion assay to monitor intracellular membrane fusion machines. Methods Enzymol 2003; 372:274-300. [PMID: 14610819 DOI: 10.1016/s0076-6879(03)72016-3] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Hodenius M, De Cuyper M, Desender L, Müller-Schulte D, Steigel A, Lueken H. Biotinylated Stealth magnetoliposomes. Chem Phys Lipids 2002; 120:75-85. [PMID: 12426077 DOI: 10.1016/s0009-3084(02)00105-6] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Dimyristoylphosphatidylethanolamine (DC(14:0)PE) and the dioleoyl analogue (DC(18:1cis)PE) were mixed with alpha-biotinylamido-omega-N-succinimidoxycarbonyl-poly(ethylene glycol) (NHS-PEG-biotin) and quantitatively converted to alpha-biotinylamido-omega-(dimyristoylphosphatidylethanolamino-carbonyl)polyethylene glycol (DC(14:0)PE-PEG-biotin) and the dioleoyl analogue DC(18:1cis)PE-PEG-biotin, respectively. As shown by thin-layer chromatography and 1H NMR spectroscopy, PEGylation of both phosphatidylethanolamine types went to completion if the reaction was performed in organic solvent in the presence of triethylamine. The resulting derivatives were successfully incorporated into both classical phospholipid vesicles and a phospholipid bilayer surrounding nanometer-sized magnetite cores. In the latter case, the so-called activated Stealth(1) magnetoliposomes were produced which very efficiently immobilized streptavidinylated alkaline phosphatase.
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Nguyen XT, Pabarue HA, Geyer RR, Shroyer LA, Estey LA, Parilo MS, Wilson KS, Prochaska LJ. Biochemical and biophysical properties of purified phospholipid vesicles containing bovine heart cytochrome c oxidase. Protein Expr Purif 2002; 26:122-30. [PMID: 12356479 DOI: 10.1016/s1046-5928(02)00503-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Liposomes containing bovine heart cytochrome c oxidase (COV) prepared by the cholate dialysis technique were purified from those devoid of the enzyme using discontinuous sucrose density ultra centrifugation to eliminate interference in proton-pumping assays. This technique was also used to purify liposomes containing cytochrome c oxidase depleted in subunit III (COV-III), a COX enzyme preparation with altered subunit structure, to assess if the technique could be applied to COX enzymes in which structural and functional changes have occurred. Upon discontinuous sucrose density ultra gradient ultracentrifugation, either COV or COV-III were separated into two bands. Liposomes devoid of enzyme sedimented into the 12% sucrose layer, whereas enzyme-containing liposomes (pCOV or pCOV-III) were found in the 13% sucrose layer. The yield of both pCOV or pCOV-III was greater than 60% (based on heme aa(3) content), suggesting a similar distribution of cytochrome c oxidase (COX) and subunit III-depleted enzyme (COX-III) in the purified liposomes. The number of COX or COX-III molecules per phospholipid vesicle in purified fractions was estimated to be two. Removal of subunit III (M(r)=29,918) from COX resulted in a 30% decrease in electron transfer activity (either in COV-III or pCOV-III) when compared with COV and pCOV, respectively. Both pCOV and pCOV-III exhibited low endogenous proton permeability, as assessed by possessing high respiratory control ratios (14 and greater) and by having similar valinomycin concentration dependencies for stimulation of electron transfer activity in the presence of saturating amounts of CCCP. COV-III and pCOV-III exhibited a 39-44% decrease in proton-pumping activity when compared with COV and pCOV. These results showed that the separation of COX containing liposomes from those lacking enzyme by sucrose density gradient centrifugation can be used to characterize the biophysical properties of these liposomes.
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Wagner A, Vorauer-Uhl K, Katinger H. Liposomes produced in a pilot scale: production, purification and efficiency aspects. Eur J Pharm Biopharm 2002; 54:213-9. [PMID: 12191694 DOI: 10.1016/s0939-6411(02)00062-0] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Intensive efforts have been made to establish a novel, scalable liposomal preparation technique suitable for the entrapment of even large proteins into liposomes. We have developed a new technique based on the principles of the ethanol injection technique. Herein, the principal item is the crossflow injection module, specifically designed for this purpose. This unit has the benefit of defined and characterized injection streams and permits liposome manufacture regardless of production scale, as scale is determined only by the free disposable vessel volumes. Previous publications demonstrated that the crossflow injection technique that we have developed meets all of the above-mentioned requirements. The present paper describes the entire three-step production process, consisting of encapsulation, separation of non-entrapped protein by continuous crossflow filtration, and retrieval of rh-Cu/Zn-SOD by additional filtration. Results of consecutive lots were compared, based on well-defined quality criteria.
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Radko SP, Chrambach A. Separation and characterization of sub-microm- and microm-sized particles by capillary zone electrophoresis. Electrophoresis 2002; 23:1957-72. [PMID: 12210247 DOI: 10.1002/1522-2683(200207)23:13<1957::aid-elps1957>3.0.co;2-i] [Citation(s) in RCA: 109] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The analytical separation and characterization of particles in the size range of sub-microm and microm diameters by capillary zone electrophoresis (CZE) has been reviewed. The theoretical basis, on which the mobility can be interpreted to provide information regarding characteristics of particle surface, has shortly been presented. Particular emphasis was put on the model dependence of that interpretation and the need in most applications to forego the classical idealized model of spherical particles with "smooth" surfaces and to apply more realistic models, which take the "hairy" surface of real particles into account. Some highlights of the literature on the CZE of polystyrene latex microspheres, organic and inorganic colloids, lipoprotein particles, viruses, liposomes, biological membrane vesicles, and biological cells have been discussed. Also summarized are the reports on the particle size dependence of mobility and peak broadening in CZE and on electrophoretic behavior of rodlike particles and particle aggregates. Finally, the effects of neutral polymers in the background electrolyte on particle mobility and peak width are reviewed.
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Cortesi R, Esposjto E, Luca G, Nastruzzi C. Production of lipospheres as carriers for bioactive compounds. Biomaterials 2002; 23:2283-94. [PMID: 12013175 DOI: 10.1016/s0142-9612(01)00362-3] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Aim of the present paper was to investigate the influence of preparation parameters on the production of lipospheres (LS) for drug delivery. LS composed of triglycerides and monoglycerides were alternatively produced by melt dispersion technique, solvent evaporation or w/o/w double emulsion method. The influence of preparation parameters, such as (a) type and amount of lipids, (b) presence and concentration of surfactants, (c) stirring speed and (d) type of stirrer was studied. In the case of LS prepared by melt dispersion, the use of a lipid composition of cetyl alcohol/cholesterol (2:1, w/w), a 5% (w/w) gelatin solution (50 bloom grades) and 1000 rpm stirring speed resulted in the production of spherical particles, with high percentage of recovery (82%, w/w) a mean diameter of 80 microm and a narrow size distribution. In the case of LS prepared by solvent evaporation, the best results in terms of LS morphology, recovery and size distribution were obtained by the use of a lipid composition of tristearin/monostearate (66:34, w/w), a 1% (w/w) PVA solution, a 750 rpm stirring speed and a 55 mm three-blade turbine rotor. The solvent evaporation method resulted in the production of LS characterised by a smaller size (20 microm mean diameter) but poor mechanical properties with respect to particles with the same composition obtained by the melt dispersion technique (170 microm mean diameter). The use of a combination of lipids and a methacrylic polymer (Eudragit RS 100) overcame this problem, resulting in the production of spherical particles, with a narrower size distribution and good mechanical properties. Two lipophilic drugs, such as retinyl acetate and progesterone, and one hydrophilic drug, sodium cromoglycate (SCG), were encapsulated in LS as model compounds. Lypophilic drugs displayed satisfactory encapsulation efficiencies (over 70% w/w), while SCG was very scarcely encapsulated (about 2% w/w). To solve this drawback, the use of a w/o/w double emulsion strategy was proposed, enabling to increase the encapsulation of SCG up to 50% w/w. Finally, in vitro drug release studies were performed, showing that all drugs were released in a control manner. In particular. the retinyl acetate release efficacy within the first 8 h was 27% of the total amount of the drug, while in the same period, the amount of progesterone released was 63%. With regard to SCG containing LS, the release of the drug was largely influenced by the type of stabiliser of the primary emulsion, in any case the SCG release reached the 100% of the total amount of drug after 5 h from the beginning of the experiment.
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Abstract
Liposome researchers have created a hugh variety of liposomal drug carriers in the past thirty years mainly by small-scale laboratory techniques using more or less well defined raw materials. Only a few of these liposomal preparations have made their way to approved drugs for clinical use in humans so far. The review gives a critical literature survey over key technologies, which are used to evaluate an appropriate lipid formula and to prepare, size, load and sterilise liposomes. It also deals with quality and shelf stability aspects of liposomal drug carriers.
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Conlan JW, Krishnan L, Willick GE, Patel GB, Sprott GD. Immunization of mice with lipopeptide antigens encapsulated in novel liposomes prepared from the polar lipids of various Archaeobacteria elicits rapid and prolonged specific protective immunity against infection with the facultative intracellular pathogen, Listeria monocytogenes. Vaccine 2001; 19:3509-17. [PMID: 11348718 DOI: 10.1016/s0264-410x(01)00041-x] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Protective immunity to intracellular bacterial pathogens usually requires the participation of specific CD8+ T cells. Natural exposure of the host to sublethal infection, or vaccination with attenuated live vaccines are the most effective means of eliciting prolonged protective cell-mediated immunity against this class of pathogens. The ability to replace these immunization strategies with defined sub-unit vaccines would represent a major advance for clinical vaccinology. The present study examines the ability of novel liposomes, termed archaeosomes, made from the polar lipids of various Archaeobacteria to act as self-adjuvanting vaccine delivery vehicles for such defined acellular antigens. Using infection of mice with Listeria monocytogenes as a model system, this study clearly demonstrates the ability of defined, archaeosome-entrapped antigens to elicit rapid and prolonged specific immunity against a prototypical intracellular pathogen. In this regard, all of the tested archaeosomes were superior to conventional liposomes.
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Lee A, Lemmon MA. Analysis of phosphoinositide binding by pleckstrin homology domain from dynamin. Methods Enzymol 2001; 329:457-68. [PMID: 11210566 DOI: 10.1016/s0076-6879(01)29107-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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Radko SP, Stastna M, Chrambach A. Size-dependent electrophoretic migration and separation of liposomes by capillary zone electrophoresis in electrolyte solutions of various ionic strengths. Anal Chem 2000; 72:5955-60. [PMID: 11140762 DOI: 10.1021/ac000661e] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The size-dependent electrophoretic migration and separation of liposomes was demonstrated and studied in capillary zone electrophoresis (CZE). The liposomes were extruded and nonextruded preparations consisting of phosphatidylcholine/phosphatidylglycerol/cholesterol in various ratios and ranging from 125 to 488 nm in mean diameter. When liposomes of identical surface charge density were subjected to CZE in Tris-HCl (pH 8) buffers of various ionic strengths (0.001-0.027), they migrated in order of their size. Size-dependent electrophoretic migration and separation of liposomes in CZE can be enhanced or brought about by decreasing the ionic strength of the buffer. It was shown that size-dependent migration is primarily a function of kappaR, where kappa(-1) is the thickness of the electric double layer (which can be derived from the ionic strength, I, of the buffer) and R, the liposome radius. Liposome mobility depends on kappaR and surface charge density in a manner consistent with that expected from the Overbeek-Booth electrokinetic theory. Thus, the relaxation effect appears to be the physical mechanism underlying the size-dependent electrophoretic separation of liposomes.
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Choice E, Ayyobi AF, Pritchard PH, Madden TD. Separation of liposomes from plasma components using fast protein liquid chromatography. Anal Biochem 1999; 270:1-8. [PMID: 10328758 DOI: 10.1006/abio.1999.4049] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We describe an efficient method for separating liposomes (large unilamellar vesicles, 120-150 nm diameter) from plasma lipoproteins employing fast protein liquid chromatography (FPLC). This method resolves very low density lipoprotein (VLDL), low-density lipoprotein, high-density lipoprotein, and other plasma components. Selective detection of liposomes (large unilamellar vesicles, 120-150 nm diameter) was achieved using either radiolabeled or fluorescent lipid probes. The liposomes were found to coelute with the earliest FPLC-eluting lipoprotein fraction, VLDL. The remaining plasma lipoprotein and protein components eluted at later times and were resolved from liposomes and VLDL. In order to separate VLDL from liposomes, we selectively precipitated the VLDL fraction from plasma using tungstophosphoric acid and magnesium chloride, prior to separation by FPLC. Furthermore, we demonstrate that this technique can be used to separate liposomes from lipoproteins in plasma samples collected after intravenous administration of liposomes to mice. This technique has wide application in studies of liposome stability in blood and, in particular, for the characterization of liposomal drug carrier systems.
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Korgel BA, van Zanten JH, Monbouquette HG. Vesicle size distributions measured by flow field-flow fractionation coupled with multiangle light scattering. Biophys J 1998; 74:3264-72. [PMID: 9635780 PMCID: PMC1299667 DOI: 10.1016/s0006-3495(98)78033-6] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The separation method, flow field-flow fractionation (flow FFF), is coupled on-line with multiangle laser light scattering (MALLS) for simultaneous measurement of the size and concentration of vesicles eluting continuously from the fractionator. These size and concentration data, gathered as a function of elution time, may be used to construct both number- and mass-weighted vesicle size distributions. Unlike most competing, noninvasive methods, this flow FFF/MALLS technique enables measurement of vesicle size distributions without a separate refractive index detector, calibration using particle size standards, or prior assumptions about the shape of the size distribution. Experimentally measured size distributions of vesicles formed by extrusion and detergent removal are non-Gaussian and are fit well by the Weibull distribution. Flow FFF/MALLS reveals that both the extrusion and detergent dialysis vesicle formation methods can yield nearly size monodisperse populations with standard deviations of approximately 8% about the mean diameter. In contrast to the rather low resolution of dynamic light scattering in analyzing bimodal systems, flow FFF/MALLS is shown to resolve vesicle subpopulations that differ by much less than a factor of two in mean size.
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Foia L, Costuleanu N, Pavel M. [The biological effects of liposome interactions with the endoplasmic reticulum]. REVISTA MEDICO-CHIRURGICALA A SOCIETATII DE MEDICI SI NATURALISTI DIN IASI 1998; 102:54-60. [PMID: 10756813] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Liposome research is a thriving field at the confluence of biophysics, cell biology and medicine. The principal medical application of liposomes is based on their potential to act as carriers for a broad spectrum of drugs and other agents, including antigens with or without immunomodulators in vaccination. Treatment of peritoneal macrophages of rats with small unilamellar vesicles of dipalmitoylphosphatidylcholine (DPPC SUV) potentiated their activation for tumor cell lysis by endotoxins. The measurement of the fluorescence anisotropy of diphenylhexatriene showed a phase transition. No phase transition was observed in the rough endoplasmic reticulum membranes of macrophages either treated or not treated with cholesterol/DPPC SUV. The synergistic effect of DPPC SUV on the tumoricidal activity of macrophages induced by endotoxins appears to be correlated with the changes in the properties of the rough endoplasmic reticulum membranes. Both effects were transient; they had the same kinetics of induction and reversion.
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Monnard PA, Oberholzer T, Luisi P. Entrapment of nucleic acids in liposomes. BIOCHIMICA ET BIOPHYSICA ACTA 1997; 1329:39-50. [PMID: 9370243 DOI: 10.1016/s0005-2736(97)00066-7] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The entrapment efficiency of three main methods used in the literature for the encapsulation of nucleic acids in liposomes were studied using 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) liposomes. In particular the reverse phase method, the dehydration/rehydration method, and the freeze/thawing method were compared to each other under standardised conditions, i.e. using in every case the same concentration of guest molecules (DNA, tRNA and ATP as low molecular weight analogue) and equally extruded liposomes. The percentage of entrapment strictly referred to the material localized inside the liposomes, i.e. particular care was devoted to ruling out the contribution of the nucleic acid material bound to the outer surface of the liposomes: this was eliminated by extensive enzymatic digestion prior to column chromatography. Depending on the conditions used, the percentage of the entrapped material varied between 10 and 54% of the initial amount. Further, the encapsulation efficiency was markedly affected by the salt concentration, by the size of liposomes, but to a lower degree by the molecular weight of the guest molecules. In general, we observed that the freeze/thawing encapsulation procedure was the most efficient one. In a second part of the work the freeze/thawing method was applied to encapsulate DNA (369 bp and 3368 bp, respectively) using liposomes obtained from POPC mixed with 1-10% charged cosurfactant, i.e. phosphatidylserine (PS) or didodecyldimethylammonium bromide (DDAB), respectively. Whereas PS had no significant effect, the entrapment efficiency went up to 60% in POPC/DDAB (97.5:2.5) liposomes. The large entrapment efficiency of DNA permits spectroscopic investigations of the DNA encapsulated in the water pool of the liposomes. UV absorption and circular dichroism spectra were practically the same as in water, indicating no appreciable perturbation of the electronic transitions or of the conformation of the entrapped biopolymer. This was in contrast to the DNA bound externally to the POPC/DDAB liposomes which showed significant spectral changes with respect to DNA dissolved in water.
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Gu JL, Nadler J, Rossi J. Use of a hammerhead ribozyme with cationic liposomes to reduce leukocyte type 12-lipoxygenase expression in vascular smooth muscle. Mol Cell Biochem 1997; 172:47-57. [PMID: 9278231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Chemically synthesized hammerhead-type ribozymes targeted against the porcine leukocyte-type 12-lipoxygenase (LO) have been developed and studied. One chimeric ribozyme consists of DNA in the non-enzymatic portions, and RNA in the enzymatic core as well as two phosphorothioate internucleotide linkages at 3' terminus. The second ribozyme consists of ribonucleotide sequences generated by in vitro transcription. In this chapter we describe methodologies to first analyze the ribozyme catalytic activity in vitro by studying cleavage of target RNA in vitro. The subsequent sections will describe how to target the catalytic ribozyme and deliver it to porcine vascular smooth muscle cells (PVSMC) by a liposome-mediated method. Finally ways to evaluate its activity to inhibit expression of the 12-LO mRNA will be presented. These results demonstrate the feasibility of using ribozymes as novel candidates for therapeutic agents to block specific gene expression in vascular cells.
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Watanabe J, Asaka Y, Mino K, Kanamura S. Preparation of liposomes that mimic the membrane of endoplasmic reticulum of rat hepatocytes. JOURNAL OF ELECTRON MICROSCOPY 1996; 45:171-176. [PMID: 8691092 DOI: 10.1093/oxfordjournals.jmicro.a023429] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
To examine the interaction between biomembranes and membrane-bound proteins, large unilamellar liposomes have been required. In the present study, we prepared liposomes from a mixture of phospholipids having a phospholipid composition similar to that in the endoplasmic reticula (microsomes) of rat hepatocytes by eight different methods. The resulting liposomes were examined by a combination of the freeze-fracture-replica procedure with biochemical methods. The freeze-thawing method of Pick (1981) gave the best results; large unilamellar liposomes that mimic the membrane of endoplasmic reticulum were obtained. Liposomes made by this method are thus suitable for analysis of the interaction between the endoplasmic reticulum membrane and membrane-bound proteins.
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Sorace JM, Rollins S, Aniagolu JU, Mergner WJ, Cole K, Swartz GM, Green SJ. Role of atheroma liposomes and malondialdehyde-modified low-density lipoproteins in complement activation. Pathobiology 1996; 64:73-8. [PMID: 8888272 DOI: 10.1159/000164012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We investigated the ability of atheroma-associated liposomes and malondialdehyde (MDA)-modified low-density lipoproteins (MDA-LDL) to activate complement. Complement activation markers C3a, Bb, C4d and SC5b-9 were measured in both normal and complement-deficient sera. We found that MDA-LDL was able to generate C3a and SC5b-9, predominantly by the alternative pathway. High-density lipoproteins modified with MDA were also capable of C3a generation although to a lesser degree. The presence of atheroma-associated liposomes did not result in detectable levels of complement activation markers. We conclude that MDA-modified lipoproteins may represent a possible source for complement activation within atherosclerotic lesions.
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Bejan A, Turcu G. Liposomes: presentation and actual applicative trends in medicine. ROMANIAN JOURNAL OF INTERNAL MEDICINE = REVUE ROUMAINE DE MEDECINE INTERNE 1995; 33:141-9. [PMID: 8646185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
In this paper the main aspects of characterization, handling and applications of liposomes are presented. In the last 25 years much attention has been focused to liposomal systems for optimization of the drug targeting. Several pathways to optimize the drug action of liposomes in various situations as cancer, microbial therapy, vaccines, oral therapy and diagnosis were tested. Certain applications of liposomes especially those implying the phagocytic cells sustain a real interest for industrial applications.
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Lalmanach Girard AC, Guillaumin JM, Thibault G, Rupin A, De Russé J, Bardos P. Inhibition of induced lymphocyte proliferation by lipid and protein components of the syncytiotrophoblast plasma membrane. Am J Reprod Immunol 1995; 33:182-9. [PMID: 7646770 DOI: 10.1111/j.1600-0897.1995.tb00883.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
PROBLEM The aim of this work was to define the respective responsibilities of the lipid and protein components of syncytiotrophoblast plasma membranes on the inhibition of lymphocyte proliferation induced in vitro. METHOD A fractionation method using octyl-beta-D-glucopyranoside enabled lipoprotein, lipid, and protein fractions to be isolated from the membrane. RESULTS The lipid fraction was shown nonspecifically to inhibit lymphocyte proliferation, to a lower extent compared with the native membrane. Alternatively, the protein fraction used as a proteoliposome contained the totality of the cytostatic effect of the native fraction. CONCLUSION These results are discussed generally in the context of the immunoregulatory role of membrane lipids and proteins and in relation to the local properties of syncytiotrophoblast plasma membrane components in fetal graft tolerance.
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