Liposomes imaging

Technetium-labeled liposome imaging for deap-seated infection,... 

Liposome image courtesy of David McCarthy and Annie Cavanagh, The School of Pharmacy, University of London, London, U.K. 

J. R. Morgan, L. A. Williams, and C. B. Howard. Technetium-labelled liposome imaging for deep-seated infection. Br. J. Radiol. 58 35-39 (1985). 

Experimental investigations of the model system of dye molecules adsorbed onto surfaces of polystyrene spheres have finuly established the sensitivity and surface specificity of the SHG method even for particles of micrometre size [117]. The surface sensitivity of die SHG process has been exploited for probing molecular transport across the bilayer in liposomes [118], for measurement of electrostatic potentials at the surface of small particles [119] and for imaging... 

For the successful treatment of human malignancy accurate staging and detection of primary and metastatic diseases is crucial. Liposomes have been shown to be useful for oncological radionuclide imaging. Profitt et al. (1983) demonstrated that stable, small. 

Begent, R. H. J., Green, A. J., Bagshawe, K. D., Jones, B. E., Keep, P. A., Searle, F., Jewkes, R. F., Barrat, G. M., and Ryman, B. E. (1982). Liposomally entrapped second antibody improves tumor imaging with radiolabelled (first) antitumor anti-body. Lancet, 2, 739-742. 

B. E. (1979). RadionucUde-labelled liposomes—A new lymph node imaging agent, Int. J. Nucl. Med. Biol.. 6, 75-83. 

Uliana, J. A., Gamble, R. C., and Baldeschwieler, J. D. (1983). Liposomal blockade of the reticuloendothelial system Improved tumor imaging with small unilamellar vesicles. Science. 220. 502-505. 

Fig. 8 Nanosystems that may function as simultaneous drug delivery and imaging agents for targeting T cells (a) liposomal systems, (b) solid biodegradable nanoparticulates, and (c) macro-molecular dendrimer complexes. PEG polyethylene glycol, Gd-DTPA gadolininum-diethylene triamine penta acetic acid. (Adapted from [48])...

Fig. 26 MR images of tumors of mice after they were injected with (a) paramagnetic av[33-specific RGD-liposomes and (b) nonspecific paramagnetic RAD-liposomes. (c, d) Fluorescence microscopy of 10 pm sections from dissected tumors revealed a distinct difference between tumors of mice that were injected with RGD-liposomes (c) or RAD-liposomes (d). Vessel staining was done with an endothelial cell-specific FITC-CD31 antibody. The red fluorescence represents the liposomes and the green fluorescence represents blood vessels. RGD-liposomes were exclusively found within the vessel lumen or associated with vessel endothelial cells (c), whereas RAD-liposomes (d) were also found outside blood vessels within the tumor (Adapted from [88])...

Covalent attachment of antibody molecules to liposomes can provide a targeting capacity to the vesicle that can modulate its binding to specific antigenic determinants on cells or to molecules in solution. Antibody-bearing liposomes may possess encapsulated components that can be used for detection or therapy (Figure 22.17). For instance, fluorescent molecules encapsulated within antibody-targeted vesicles can be used as imaging tools or in flow cytometry... 

Truneh, A., Machy, P., and Horan, P.K. (1987) Antibody-bearing liposomes as multicolor immunofluores-cent markers for flow cytometry and imaging./. Immunol. Meth. 100, 59-71. 

Concerning the nature and structure of such amyloid peptide or protein channels, oligomers with annular morphologies have in fact been observed by EM for a-synuclein (Lashuel et al., 2002) and equine lysozyme (Malisauskas et al., 2003) even in the absence of any lipids or membranes. Channel-like structures have also been reconstituted in liposomes and observed by SFM for A/ i 4o, A/ j 42, human amylin, a-synuclein, ABri, ADan, and serum amyloid A (Fig. 5A Lin et al., 2001 Quist et al., 2005). Doughnut-shaped structures with a diameter of 10-12 nm and a central hole size of 1-2 nm (Fig. 5B) were imaged on top of lipid membranes (Quist et al., 2005). However, the radius of curvature of the SFM tips meant that it is not possible to say whether the pores were really traversing the lipid bilayer. 

Figure 4 A set of gamma camera images of a rabbit intravenously injected with Tc-99m-LEH. Twenty-five percent of blood was exchanged with liposome-encapsulated hemoglobin (LEH) (hypovolemic) and the animal was imaged using a gamma camera at various times after infusion. The images clearly show a prolonged circulation of LEH as evidenced by the continued grayscale intensity in heart.

Goins BA, Phillips WT. The use of scintigraphic imaging as a tool in the development of liposome formulations. Prog Lipid Res 2001 40 95. 

Besides drug delivery, liposomes have also gained wide acceptance in other fields such as diagnostic imaging (4,5) and vaccines. In this chapter we will focus our attention specifically on the conjugation of peptides to liposomes. We will outline the major techniques involved, present some applications of liposomes-peptides constructs, and mainly discuss their use as vaccines. 

Dagar S, et al. VIP grafted sterically stabilized liposomes for targeted imaging of breast cancer in vivo studies. J Control Release 2003 91 123. 

Morphology. Structural details were visualized by cryo-TEM. Figure 1A is a cryo-TEM image of a sample with an entrapped oligonucleotide-to-lipid ratio of 0.13 mg/mg. It confirms the coexistence of unilamellar liposomes with bi- and multilamellar liposomes. The membranes of the latter are in close contact. The inset of Figure 1A is an expanded view of a multilamellar... 

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